This handy **Spectrum Math Grade 4 Answer Key Chapter 8 Lesson 8.5 Triangles** provides detailed answers for the workbook questions.

## Spectrum Math Grade 4 Chapter 8 Lesson 8.5 Triangles Answers Key

A triangle is a polygon with 3 sides. Some examples are equilateral, scalene, isoceles, right, obtuse, and acute.

In a scalene triangle, all 3 sides have different lengths. Its angles are also all different.

In an equilateral triangle, all 3 sides are the same length. All three angles equal 60°.

A right triangle has 1 right angle.

In an isosceles triangle, 2 sides have equal lengths. Two of its angles are also equal.

In an acute triangle, all angles are less than 90°.

An obtuse triangle has 1 angle that measures more than 90°.

**Identify each of the triangles.**

Question 1.

a.

Answer:

**Right Triangle**

Explanation:

A triangle is a polygon with 3 sides. The above given triangle is right triangle. A right triangle has only one right angle.

b.

Answer:

**Scalene Triangle**

Explanation:

A triangle is a polygon with 3 sides. The above given triangle is scalene triangle. In scalene triangle, all three sides have different lengths and angles.

Question 2.

a.

Answer:

**Isosceles Triangle or obtuse Triangle **

Explanation:

A triangle is a polygon with 3 sides. The above given triangle is isosceles triangle or obtuse triangle.

In isosceles triangle, two sides have equal lengths and two of its angles are also equal.

An obtuse triangle has one angle that measures more than 90°.

b.

Answer:

**Equilateral Triangle or acute Triangle **

Explanation:

A triangle is a polygon with 3 sides. The above given triangle is equilateral triangle or acute triangle.

In an equilateral triangle, all three sides have the same length. All three angles are equal to 60°.

In an acute triangle, all angles are less than 90°.