Geometry Vocab

Lines

100

Two lines that are the same distance apart and will never touch

Parallel lines

200

Lines that intersect to form a right angle

Perpendicular

300

Has one endpoint and continues in one direction forever

A ray

400

Part of a line

A line segment

500

Any closed figure with at least 3 sides

A polygon

Angles

100

The name of a 90^o angle

A right angle

200

An angle that is less than 90 degrees

Acute angle

300

An angle greater than 90^o

Obtuse angle

400

The number of degrees in a straight angle

180^o

500

The tool used to measure angles

A protractor

Triangles

100

A triangle with the same length sides

Equilateral triangle

200

A triangle with two sides the same length

Isosceles triangle

300

A triangle with one angle greater than 90^o

An obtuse triangle

400

A triangle with a 90^o angle AND no sides the same length

A right, scalene triangle

500

Total value of all angles in every triangle

180^o

Quadrilaterals

100

The number of sides on a quadrilateral

Four

200

Total number of degrees all angles of a quadrilateral

360^o

300

A quadrilateral with two sets of parallel sides and 4 right angles

A rectangle

400

A quadrilateral with two sets of opposite, parallel, congruent sides, not necessarily with right angles

A rhombus

500

A quadrilateral with only one pair of opposite, parallel sides

A trapezoid

Miscellaneous

100

The name of a 6 sided figure

A hexagon

200

The name of a 5 sided figure

A pentagon

300

A right triangle has one angle that is 45^o. What is the measure of the 3rd angle?

45^o

400

A quadrilateral has 3 angles measuring 90^o, 100^o, and 70^o. What is the measure of the 4th angle?

100^o

500

A boat has a sail with one pair of perpendicular lines, and two sides the same length. What kind of triangle is it?

Right Isosceles