Find the Perfect Square Trinomial r^2+20r

$r^{2} + 20 r$

Step 1

To find the $c$ value $c = {(\frac{b}{2})}^{2}$ , divide the coefficient of $r$ by $2$ and square the result.

Divide $20$ by $2$ .

$10^{2}$

Raise $10$ to the power of $2$ .

$100$

Step 2

Add $100$ to get the perfect square trinomial.

$r^{2} + 20 r + 100$