The answer should be A, if he marked it up 70% just multiply 66 by 1.7 for your answer.
Your answer is 16 because you have to multiply b and c but it has to be squared and then you subtract 400 by 144 and get 256 and the square root of that is 16
It is 0.5
Hope it helped!!
That equals 27 hope this helps
Answer:
1944 Inches Squared
Step-by-step explanation:
Surface area Formula for a Cube:
![A = 6a^2](https://tex.z-dn.net/?f=A%20%3D%206a%5E2)
The "edge", which is also the side, is 18 inches.
![a = 18](https://tex.z-dn.net/?f=a%20%3D%2018)
Solve the formula.
![A= 6a^2 = 6(18)^2 = 6 * 18^2\\18^2 = 324\\324 * 6 = 1944\\A=1944](https://tex.z-dn.net/?f=A%3D%206a%5E2%20%3D%206%2818%29%5E2%20%3D%206%20%2A%2018%5E2%5C%5C18%5E2%20%3D%20324%5C%5C324%20%2A%206%20%3D%201944%5C%5CA%3D1944)
The cube's surface area should be 1944 square inches.