# How do you evaluate b=sqrt(a^2-c^2) given a=29 and c=20?

Nov 24, 2016

$b = 35.23$ rounded to the nearest 100th.

#### Explanation:

You substitute $29$ for $a$ and $20$ for $c$ in the equation and then do the math to solve for $b$:

$b = \sqrt{{29}^{2} - {20}^{2}}$

$b = \sqrt{29 \cdot 29 - 20 \cdot 20}$

$b = \sqrt{841 - 400}$

$b = \sqrt{1241}$

$b = 35.23$

Nov 24, 2016

$b = 21$
$\Rightarrow b = \sqrt{{29}^{2} - {20}^{2}}$
$= \sqrt{841 - 400} = \sqrt{441} = 21$