Chapter 9, Problem 20CR

To determine

Tofind:The unknown length

Answer to Problem 20CR

  $b=4\sqrt{2}$

Explanation of Solution

Given information:

Formula used:

Pythagoras Theorem- $a^2+b^2=c^2$

Where $a$ and $b$ are legs of right angled triangle and $c$ is hypotenuse

Calculation:

In the given triangle-

  $\begin{array}{l}{a}^2+b^2=c^2\\ \Rightarrow {\left(7\right)}^2+b^2={\left(9\right)}^2\\ \Rightarrow 49+b^2=81\\ \Rightarrow b^2=81-49\\ \Rightarrow b^2=32\\ \Rightarrow b=\sqrt{32}\\ \Rightarrow b=\sqrt{4·4·2}\\ \Rightarrow b=\sqrt{4^2·2}\\ \Rightarrow b=4\sqrt{2}\end{array}$