The formula that you would probably use is a2 +b2 = c2 since the triangle is isosceles, a and b are the same, you would set the formula up as 7(square root)3 + 7(square root)3 = c2 *when calculator used 42=c2 6.48=c
Since the price is now 15% less you would first find what 15% of 25 is by using 25*.15 and get 3.25 then you subtract that from 25 and get 25-3.25= $21.75
