## Congruent Angles

In geometry, 2 figures or objects are congruent if they have the same shape and size, or if one has the same shape and size as the mirror image of the other. Definitions of Congruent Angles Angles are congruent if they have the same angle measure in degrees. They can be at any orientation on

## Complementary Angles

Complementary comes from Latin completum meaning “completed“, because the right angle is thought of as being a complete angle. Definition of Complementary Angles Complementary angles are 2 angles whose measures add up to 90o. For example 2 puzzle pieces that form one 90o angle when they are put together. Complementary angles are always in a pair. One

## How To Find if Triangles are Congruent

Triangles are congruent when all corresponding sides & interior angles are congruent. The triangles will have the same size & shape, but 1 may be a mirror image of the other. 2 triangles are congruent if they have: exactly the same three sides and exactly the same three angles. We don’t have to know all 3

## Volume and Area of a Sphere

Definition A sphere is a perfectly round geometrical object in 3D space that is the surface of a completely round ball. Sphere Facts Here are some interesting facts about sphere: It is perfectly symmetrical All points on the surface are the same distance “r” from the center It has no edges or vertices (corners) It

## Kite

A Kite is a flat shape with straight sides. It has 2 pairs of equal-length adjacent sides. Characteristics of Kite Two pairs of sides Each pair is 2 equal-length sides that are adjacent The angles are equal where the 2 pairs meet Diagonals (dashed lines) cross at right angles, and one of the diagonals bisects

## Cylinder: Definition, Properties, Types, Surface Area, Volume

“cylinder” was named base on Latin (Cylindrus) and Greek (Kylindros). It means “roll”, “roller”, and “tumblr”. Cylinder is a shape that is common in daily life such as can, money box, toilet tissue roll, tumbler, etc. Definition of Cylinder Cylinder is three-dimensional shape with two congruent parallel circular shape (circles or ellipse). There is also

In the lesson below, you will learn about how to identify whether angles are adjacent. Definition Adjacent angles are 2 angles that have a common vertex & a common side. The vertex of an angle is the endpoint of the rays that form the sides of the angle. The common vertex and common side we mean here are

## Alternate Exterior Angles

Definition When 2 lines are crossed by another line (Transversal): Alternate Exterior Angles are a pair of angles on the outer side of each of those two lines but on opposite sides of the transversal. How to remember the angle pairs are on Alternate sides of the Transversal, and they are on the Exterior of

## Alternate Interior Angles

Definition When two lines are crossed by another line (Transversal): Alternate Interior Angles are a pair of angles on the inner side of each of those 2 lines but on opposite sides of the transversal. How To remember: The angle pairs are on Alternate sides of the Transversal, and they are on the Interior of

## Sphere: Definition, Properties, Surface Area, Volume, Spheroid, and Hemisphere

Sphere is like circle in two-dimensional shape. But it is three-dimensional shape. Sphere things in daily life are like bubbles, marbles, balloons, balls, water drops, etc. Definition of Sphere Sphere is three-dimensional shape. It is a set of points that has same distance to the center. The distance is called radius (r). besides that, it