18 - 7x = -20.52.5 = 7xx = 5/14 (c)
9514 1404 393
Answer:
8) 42 in²
9) 33 cm²
10) 112 yd²
Step-by-step explanation:
8) The area is given by the formula ...
A = 1/2(b1 +b2)h
A = (1/2)(9 in +5 in)(6 in) = 42 in²
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9) The area is half the product of the lengths of the diagonals.*
A = 1/2(d1)(d2)
A = 1/2(6 cm)(11 cm) = 33 cm²
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10) As in the previous problem, ...
A = 1/2(14 yd)(16 yd) = 112 yd²
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* This formula works for any quadrilateral with perpendicular diagonals.
