Answer:
i = {√(P-180)/20}+ 3
Step-by-step explanation:
Here, we simply need to make i the subject of the formula
that would be;
P -180 = 20(i-3)^2
Divide through by 20
(P-180)/20 = (i-3)^2
Find the square root of both sides
sqr (P-180)/20 = i-3
i = {√(P-180)/20}+ 3