Chapter 13.8, Problem 68HP

To determine

Find the average of a, b, c, d and f.

Answer to Problem 68HP

The average of a, b, c, d and f are ${54}^{\circ }$ .

Explanation of Solution

Given: It is given in the question that the two figure is

  

Concept Used:

In this, use the concept of angle sum property i.e. ${180}^{\circ }$ .

Calculation: Since, the sum of all the angle of triangle is ${180}^{\circ }$ .

  $\begin{array}{l}a+b+c+d+f+{90}^{\circ }={180}^{\circ }+{180}^{\circ }\\ a+b+c+d+f={360}^{\circ }-{90}^{\circ }\\ a+b+c+d+f={270}^{\circ }\end{array}$

Average of the five is $\frac{{270}^{\circ }}{5}={54}^{\circ }$

Conclusion:

The correct option is ${54}^{\circ }$ .