## 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 … Continue reading "Congruent Angles"

## 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 … Continue reading "Complementary Angles"

## 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 … Continue reading "How To Find if Triangles are Congruent"

## 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 … Continue reading "Volume and Area of a Sphere"

## 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 … Continue reading "Kite"

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 … Continue reading "Adjacent Angles"

## 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 … Continue reading "Alternate Exterior Angles"

## 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 … Continue reading "Alternate Interior Angles"

## Vertical Angles

Definition Vertical Angles are the angles opposite each other when two lines cross In this case, “Vertical” means they share the same corner point (Vertex), not the usual meaning of up-down. Example a° and b° are vertical angles. Vertical Angles are Congruent Angles The interesting thing here is that vertical angles are congruent angles: a° … Continue reading "Vertical Angles"

## Lines of Symmetry of Plane Shapes

The line of symmetry is the axis or imaginary line that passes through the center of the shape or object and divides it into identical halves. How to find a shape has a Line of Symmetry ? You can find a shape has a Line of Symmetry or not by folding it When the folded … Continue reading "Lines of Symmetry of Plane Shapes"