Chapter 12, Problem 1STP

To determine

To calculate:To classify the below triangle by its angles -

Answer to Problem 1STP

The triangle is a right-angled triangle.

The answer is $C.$ right

Explanation of Solution

Given information:

Given triangle is :

Formula Used:

In a triangle, sum of the three angles is $180°$ .

Definition of a right-angled triangle - A right triangle or right-angled triangle is a triangle in which one angle is a right angle.

Calculation:

Given triangle is:

The sum of two given angles is : $31°+59°=90°$

From the above definition of a triangle −

Third angle is :

  $180°-90°=90°$

From the above definition of a right-angled triangle, since one of the angles is $90°$ , the given triangle is a right-angled triangle.

Conclusion:

The triangle is a right-angled triangle.

The answer is $C.$ right