Explanation:
Hey there!
Given;
The given figure is a Right angled triangle, taking reference angle as angle B.
Hypotenuse= AB=5
Base= CB= 4
Perpendicular= AC=b
Using Pythagorean theorem.
![{h}^(2) = {p}^(2) + {b}^(2)](https://img.qammunity.org/2021/formulas/mathematics/high-school/nwicczee74p9gg31iv418s9sqnp69ofmcc.png)
![p = \sqrt{ {h}^(2) - {b}^(2) }](https://img.qammunity.org/2021/formulas/mathematics/college/kvlg5j62cxhjvrg5mjlk6xvm91x954grxm.png)
Put all values.
![b = \sqrt{ {5}^(2) - {4}^(2) }](https://img.qammunity.org/2021/formulas/mathematics/high-school/xphywpeh8g6cod6irpa7alymbnw1z1u9yz.png)
![b = √(25 - 16)](https://img.qammunity.org/2021/formulas/mathematics/high-school/7khsrmrz8kyt20a5f1it6nqf71rhtr0x3f.png)
![b = √(9)](https://img.qammunity.org/2021/formulas/mathematics/high-school/yuc1papm7ldrgcza4hzhvvafrstgpcg33t.png)
Therefore, the value of b is 3.
Hope it helps...