Page 19 - Mathematics Teaching Material Two Dimensional Figure

Mathematics Teaching Material Two Dimensional Figure

7. Triangle

What is a triangle ?

Triangle is a plane that has three angles and three legs.

Types of triangles :

a. Based on the size of the angle :

1. Acute triangle: a triangle whose angles are less than 90
2. Right-angled triangle: a triangle whose angles measure 90

3. Obtuse triangle: a triangle whose angle is greater than 90

b. Based on side length :

1. Arbitrary Triangle: a triangle whose three sides are not the same length

2. Equilateral triangle: a triangle whose three sides are the same length

3. Isosceles triangle: a triangle whose two sides are the same length

Area of a triangle = × ×

Around = a + b + c

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