# 2nd 3rd grde geometry

## 38 terms

### acute angle

an angle whose measure is between 0 degrees and 90 degrees

### angle

the region between two rays

### area

a measurement of the region enclosed by the sides of a polygon Area is always expressed in squared units.

### centimeter

a metric unit of length; 1/100 of a meter

### circle

the set of all points in a plane that are the same distance (called the radius) from a given point (the center)

### congruent

having the same size, shape and measure

### degrees Celsius

unit of temperature in the metric system. Freezing = 0°C, Boiling = 100°C

### degrees Fahrenheit

unit of temperature in the English (Customary) system of measurement. Freezing = 32°F, Boiling = 212°F

### diameter

a line segment passing through the center of a circle with endpoints on the circle.

### edge

the intersection of a pair of faces in a three-dimensional figure

### equilateral triangle

a triangle with three equal sides and three equal angles

### face

the plane figures that make up a solid figure

### foot

a customary unit of length 1 foot = 12 inches

### hexagon

a polygon with six sides

### inch

a customary unit of length 12 inches = 1 foot

### isosceles triangle

a triangle with at least two equal sides and two equal angles

### kilometer

a unit of measurement for length in the metric system. 1 kilometer = 1000 meters

### meter

the standard unit of length in the metric system 1 meter = 100 centimeters

### millimeter

A metric unit of measurement for length. 1 meter = 1000 millimeters

### obtuse angle

An obtuse angle is greater than 90 degrees but less than 180 degrees

### parallelogram

A quadrilateral with opposite sides that are parallel and of equal length and with opposite angles that are equal

### perimeter

the distance around the outside of a shape

### plane figure

a figure of which all points lie in the same plane

### polygon

a closed plane figure (no gaps or openings) made with 3 or more sides and angles

a four-sided polygon

the distance from the center of a circle to any point on the circumference

### rectangle

a quadrilateral with four right angles and two pairs of opposite equal parallel sides

### rhombus

a parallelogram with four equal sides and equal opposite angles

### right angle

An angle that measures exactly 90 degrees.

### scalene triangle

a triangle in which all three sides are different lengths

### side

a line or curve on the edge of a shape that joins its vertices.

### solid figure

a 3-dimensional figure having length, width, and height.

### square

a quadrilateral with four equal sides, four right angles, and opposite sides that are parallel

### thermometer

instrument for measuring temperature

### triangle

a polygon with three sides

### trapezoid

a quadrilateral with two parallel sides

### vertex

point where surfaces or line segments meet; corner (plural: vertices)

### yard

A unit of measurement of length in the English (Customary) measurement system; 3 feet = 1 yard