Answer:
A =530.66 cm^2
Step-by-step explanation:
A DVD is a circle so we can use the formula for area of a circle
A = pi r^2
We can find the radius from
r = d/2 where d is the diameter
r = 26/2
r = 13
A = pi *13^2
A = pi *169
Substituting in for pi
A = (3.14) * 169
A =530.66
Just use the Pythagorean Theorem
(9 +x)^2 = 15^2 + x^2
x^2 + 18x + 81 = 225 + x^2
18x = 144
x = 8
So the three sides of the triangle are
15, 8 and 17