Question

Write an equation of the circle with center (7,4) and diameter 10

Answer 1

Circles follow ghe equations
(x-h)^2 + (y-k)^2 =r^2
with center (h,k) and radius r
for this circle it would be
(x-7)^2 + (y-4)^2 = 100

Answer 2

If the diameter is 10, then the radius is 5. (x-7)² + (y-4)² = 5² 
The answer is (x-7)² + (y-4)² = 25