Understanding Angles and Triangles

Front

Parallel lines

Back

Lines that never meet

Front

Corresponding angles

Back

Equal angles in matching corners

Front

Alternate angles

Back

Equal angles on opposite sides

Front

Vertically opposite angles

Back

Equal angles formed by intersecting lines

Front

Adjacent angles

Back

Angles sharing a common arm

Front

Complementary angles

Back

Angles adding up to 90°

Front

Supplementary angles

Back

Angles adding up to 180°

Front

Acute angle

Back

Angle less than 90°

Front

Right angle

Back

Angle equal to 90°

Front

Obtuse angle

Back

Angle more than 90° but less than 180°