English Words for "Geometry" | ACT Vocabulary

slope

noun

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l

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oʊ

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e

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the measure of how steep a line is, found by dividing the change in height by the change in horizontal distance

Example

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The slope of the line between points (1, 2) and (3, 6) is 2.

A slope of zero means the line is perfectly horizontal.

arc

noun

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(geometry) a part of a circle, which is curved

radian

noun

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a unit for measuring angles, defined by the angle made when the radius of a circle is laid along its edge

radius

noun

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eɪ

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iə

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the length of a straight line drawn from the center of a circle to any point on its outer boundary

diameter

noun

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ia

aɪæ

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a straight line from one side of a round object, particularly a circle, passing through the center and joining the other side

perimeter

noun

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the total length of the external boundary of something

circumference

noun

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ɜ

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(geometry) the length of the external boundary of a curved shape, especially a circle

area

noun

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ea

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the measurement of a piece of land or a flat surface

volume

noun

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ju

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the amount of space that a substance or object takes or the amount of space inside an object

What is "volume"?

Volume refers to the amount of space occupied by a substance or object. It can also refer to the capacity or internal space within an object. Volume is typically measured in units such as liters or cubic meters and is calculated by multiplying the length, width, and height of an object or by using specific formulas for irregular shapes. In the context of liquids or gases, volume is often expressed as the amount of fluid that can be contained within a given container. Volume is a fundamental concept in physics, chemistry, engineering, and other scientific disciplines, and it plays a crucial role in various applications, including the design of containers and the measurement of quantities in everyday life.

angle

noun

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æ

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the space between two lines or surfaces that are joined, measured in degrees or radians

right angle

noun

/ɹˈaɪt ˈæŋɡəl/

an angle measuring exactly 90 degrees

oblique angle

Grammatical Information:

compound noun

vertical angle

noun

/vˈɜːɾɪkəl ˈæŋɡəl/

one of a pair of opposite angles made by two intersecting lines, which are always equal

Grammatical Information:

compound noun

interior angle

noun

/ɪntˈiəɹɪɚɹ ˈæŋɡəl/

an angle formed between two sides of a polygon that lies inside the shape

Grammatical Information:

compound noun

consecutive angle

noun

/kənsˈɛkjuːtˌɪv ˈæŋɡəl/

pairs of angles that share a common side and vertex in a polygon or between intersecting lines

Grammatical Information:

compound noun

obtuse

Adjective

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(of angle) greater than 90 degrees but less than 180 degrees

acute

protractor

noun

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a measuring instrument used to measure and draw angles

What is a "protractor"?

A protractor is a tool used to measure and draw angles. It is usually a flat, semicircular or circular device marked with degree measurements from 0 to 180 or 360. The protractor has a straight edge for aligning with a line or point, while the curved side is used to measure the angle between two meeting lines. Protractors are commonly used in geometry, drafting, carpentry, and construction to ensure accurate angle measurements for various projects. They come in different sizes and types, including digital versions for easier reading.

perpendicular

Adjective

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(of lines or planes) intersecting each other at a 90 degree angle

oblique

polygon

noun

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(geometry) a flat shape consisting of three or more straight sides

tetrahedral

Adjective

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characterized by or resembling a tetrahedron, which has four triangular faces

pentagon

noun

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n

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a geometric shape with five angles and five straight sides

epicycle

noun

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ɛ

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y

aɪ

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a small circle whose center moves around the circumference of a larger circle

hyperbola

noun

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a geometric curve formed by the intersection of a plane with two cones, resulting in two symmetrical branches

parabola

noun

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ɜ

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æ

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(geometry) a symmetrical open curve that is similar to the path of an object thrown into the air passes till it falls back to earth

acute triangle

noun

/ɐkjˈuːt tɹˈaɪæŋɡəl/

a triangle in which all three interior angles are less than 90 degrees

Grammatical Information:

compound noun

equilateral triangle

noun

/ˌiːkwᵻlˈæɾɚɹəl tɹˈaɪæŋɡəl/

a type of triangle with all three sides of equal length

Grammatical Information:

compound noun

scalene triangle

noun

/skˈeɪliːn tɹˈaɪæŋɡəl/

a type of triangle that has all three sides of different lengths

Grammatical Information:

compound noun

isosceles

Adjective

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describing a triangle with at least two sides of equal length

hypotenuse

noun

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the longest side of a right-angled triangle, opposite the right angle, and defined as the side opposite the right angle in a right-angled triangle

right circular cylinder

noun

/ɹˈaɪt sˈɜːkjʊlɚ sˈɪlɪndɚ/

a three-dimensional geometric shape with two parallel circular bases connected by a curved surface at a right angle to the bases

Grammatical Information:

compound noun

rectangular pyramid

noun

/ɹɛktˈænɡjʊlɚ pˈɪɹɐmˌɪd/

a three-dimensional geometric shape that has a rectangular base and four triangular faces that meet at a single point called the apex

Grammatical Information:

compound noun

asymmetry

noun

a

eɪ

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ɪ

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(geometry) a lack of symmetry or equivalence in shape or size between the two sides or parts of something

symmetry

vertex

noun

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a point where two or more lines, edges, or rays meet to form an angle, or the point at which the sides of a polygon intersect

diagonal

noun

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ia

aɪæ

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a straight line connecting opposite corners of a flat shape at an angle

congruent

Adjective

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(in geometry) describing shapes of the same size and form

incongruent

base

noun

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eɪ

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the side of a geometric shape, usually the one considered as the bottom, from which the height is measured

parallel

noun

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a pair of geometric figures, such as lines or planes, that do not meet or intersect, no matter how far they are extended

line of symmetry

noun

/lˈaɪn ʌv sˈɪmətɹi/

a line that divides a shape into two congruent parts

Grammatical Information:

compound noun

geometric series

noun

/dʒˌiːoʊmˈɛtɹɪk sˈɪɹiz/

a series of numbers in which each term after the first is found by multiplying the previous term by a fixed, non-zero number

Grammatical Information:

compound noun

surface area

noun

/sˈɜːfɪs ˈɛɹiə/

the total area that the surface of a three-dimensional object occupies

Grammatical Information:

compound noun

transversal

Adjective

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(of a line) intersecting two or more other lines at different points

quadrant

noun

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one-fourth of a circle, formed by two perpendicular radii and the connecting arc

asymptote

noun

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a straight line that a curve approaches indefinitely but never intersects, characterizing the limiting behavior of the curve

to bisect

Verb

b

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aɪ

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ɛ

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to divide something into two equal parts

Grammatical Information:

transitive

tangent

noun

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æ

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ə

n

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a straight line that touches a curve or surface at exactly one point, known as the point of tangency

chord

noun

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a straight line segment that connects two points on the edge of a circle

to translate

Verb

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(geometry) to move a shape or figure from one position to another without rotating, resizing, or otherwise altering its shape

Grammatical Information:

transitive

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You learned 46 words from ACT Geometry Vocabulary. To improve learning and review vocabulary, start practicing.

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