SaiBook.us Geometry

Lesson Example Discussion Quiz: Class Homework

Example

Title: Perimeter of Triangle(based on angles)

Grade: 4-a Lesson: S1-L8

Explanation: The best way to understand geometry is by looking at some examples. Take turns and read each example for easy understanding.

Examples:

Triangle XYZ is a right triangle with angle Y measuring 90 degrees. If angle X measures 30 degrees, find the measure of angle Z.

Step 1a

In a right-angled triangle, the sum of all angles always equals 180 degrees. So, for any right-angled triangle, we can say that Angle X + Angle Y + Angle Z = 180 degrees.

$1a$

Explanation: In a right-angled triangle, the sum of all angles is 180 degrees.

Step 1b

Given Angle Y is a right angle of 90 degrees and Angle X is 30 degrees, we need to determine Angle Z.

Explanation: We need to find Angle Z, given that Angle Y is a right angle with a measure of 90 degrees and Angle X has a measure of 30 degrees.

Step 1c

Substitute the values : 30 degrees + 90 degrees + Angle Z = 180 degree

Angle Z = 180 degrees - 120 degrees

Angle Z = 60 degrees.

Explanation: Angle Z equals 60 degrees. To determine this value, subtract 120 degrees from 180 degrees.

Step 1d

So, the measure of angle Z is 60 degrees.

Explanation: The measurement of angle Z is 60 degrees.