Cards | 10 |

Topics | Angles Around Lines & Points, Coordinate Grid, Cylinders, Dimensions, Parallelogram, Triangle Classification, Triangle Geometry |

Angles around a line add up to 180°. Angles around a point add up to 360°. When two lines intersect, adjacent angles are **supplementary** (they add up to 180°) and angles across from either other are **vertical** (they're equal).

The coordinate grid is composed of a horizontal **x-axis** and a vertical **y-axis**. The center of the grid, where the x-axis and y-axis meet, is called the **origin**.

A cylinder is a solid figure with straight parallel sides and a circular or oval cross section with a radius (r) and a height (h). The **volume** of a cylinder is π r^{2}h and the **surface area** is 2(π r^{2}) + 2π rh.

A circle is a figure in which each point around its perimeter is an equal distance from the center. The **radius** of a circle is the distance between the center and any point along its perimeter (AC, CB, CD). A **chord** is a line segment that connects any two points along its perimeter (AB, AD, BD). The **diameter** of a circle is the length of a chord that passes through the center of the circle (AB) and equals twice the circle's radius (2r).

A parallelogram is a quadrilateral with two sets of parallel sides. Opposite sides (a = c, b = d) and angles (red = red, blue = blue) are equal. The area of a parallelogram is base x height and the perimeter is the sum of the lengths of all sides (a + b + c + d).

An **isosceles** triangle has two sides of equal length. An **equilateral** triangle has three sides of equal length. In a **right** triangle, two sides meet at a right angle.

A triangle is a three-sided polygon. It has three interior angles that add up to 180° (a + b + c = 180°). An exterior angle of a triangle is equal to the sum of the two interior angles that are opposite (d = b + c). The **perimeter** of a triangle is equal to the sum of the lengths of its three sides, the **height** of a triangle is equal to the length from the **base** to the opposite **vertex** (angle) and the **area** equals one-half triangle base x height: a = ½ base x height.