The formula for finding the height of an octagon from only one side is h=s(1 + the square root of 2). S is the length of one side. Your formula would be h=18(1 + the square root of 2). h=18+18(the square root of 2)
h=18 + 25.4558
h=43.4558
Hope this helps!! :) And the decimal is rounded, just so you know ;). If your teacher likes everything in simplest radical form, then just don't convert the 18*the square root of 2 into a decimal and solve as you normally would.
The dimensions of all parts of Triangle B is 4 times that of A A = 1/2 b * h for the given triangle A = 1/2 * 4b * 4h A = 1/2 * 16 * b * h A = 16 * (1/2 * b * h)
The area of the new triangle is 16 times the old. 16 * 15 = 240 cm^2 240 cm^2 <<<<< answer