Geometry basics

A 2d pattern that you can fold to form a 3d figure shows all surfaces in one view

the top view, front view, and right view of a 3D figure

A form of pictorial drawing in which all three drawing axes form equal angles of 120 degrees with the plane of projection.

A location in space. shown with capital letter

a straight path that extends without end in opposite directions

named by points on line or lowercase letter

- flat surface named with capital letter or three letters on plane

- part of a line with two endpoints

- a part of a line that starts at an endpoint and extends forever in one direction

• two rays that have a common endpoint and form a line

points that lie on the same line

• points that lie on the same plane

the set of all points

a statement that is accepted as true without proof

• A point where lines intersect.

- same size and shape

- A point that divides a segment into two congruent segments

- a ray that divides an angle into two congruent angles

A figure formed by two rays with a common endpoint

Angles that have a common side and a common vertex (corner point).

A pair of opposite congruent angles formed by intersecting lines

Two angles whose sum is 90 degrees

Two angles whose sum is 180 degrees

A pair of adjacent angles whose noncommon sides are opposite rays form straight line.

M=a+b/ 2

(x₁+x₂)/2, (y₁+y₂)/2

s²

1/2bh

Bh

πr²

- 2πr

- A straight line passing from side to side through the center of a circle or sphere.

- r=d/2

d = √[( x₂ - x₁)² + (y₂ - y₁)²]