SOLUTION: David is making a triangular plaque for his dad. He cuts a triangular piece of wood from a rectangular board of wood. The triangle has a base of 15 inches and a height of 9 inches.

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Question 1113528: David is making a triangular plaque for his dad. He cuts a triangular piece of wood from a rectangular board of wood. The triangle has a base of 15 inches and a height of 9 inches. The rectangular board has a length of 20 inches and a width of 12 inches. He wants to figure out the area of the piece of wood that is left.
Part A: Calculate the areas of the triangle plaque and the original rectangular board and explain how you found the answer.
Answer by ikleyn(52778) About Me  (Show Source):
You can put this solution on YOUR website!
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The area of the original rectangular board is the product of its dimensions  20*12 = 240 square inches.


The area of triangle is half the product of the base length by its height  %281%2F2%29%2A15%2A9 = 67.5 square inches.


The area of the piece of wood which is left is the difference  240 - 67.5 = 172.5 square inches.