Solve the formula A= pi r^2 for r

sqrt(A/pi)= r

Step-by-step explanation:

A= pi r^2

Divide each side by pi

A/pi= pi r^2/pi

A/pi=  r^2

Take the square root of each side

sqrt(A/pi)= sqrt( r^2)

sqrt(A/pi)= r

first, you divide the triangle in two, tô form a retangle triangle. after, using pythagoream theorem:

18^2 = 14^2 + (x/2)^2

(x^2/4) + 196 = 324

x^2/4 = 324 - 196

x^2/4 = 128

x^2 = 512

x = √512

x = √2^9

x = 16√2 cm

i hope i you.