You can work out the diagonal by using Pythagoras theorem. (a^2 = b^2 + c^2)
As it is a square, all 4 sides are the same so it would be:
11.2^2 + 11.2^2 = diagonal^2
250.88 = diagonal^2
Square root both sides to get what the diagonal is equal to.
diagonal is 15.8 cm
The rate is 12 per carton.
You need 3/5 of the 35 gallons of paint, so all you need to do is divide 35 by 5 to get 7 and multiply that by 3 to get 21. 3/5 of 35 is 21. Then, if each gallon is $22, you just multiply 21x22 to get your cost.
C. C(t)=8(3)^t
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