9514 1404 393
Answer:
10 cm
Explanation:
The given area is the product of the side lengths, so the angle between them must be 90°.
Area = ab·sin(C) . . . . . where C is the angle between sides 'a' and 'b'.
48 cm² = (8 cm)(6 cm)·sin(C)
1 = sin(C) ⇒ C = 90° . . . . . . . . divide by 48 cm², find the arcsin
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The diagonal of the parallelogram (rectangle) can be found from the Pythagorean theorem. (Using the law of cosines would give the same result.)
d² = 8² +6² = 64+36 = 100
d = √100 = 10 . . . . cm
The length of the diagonal is 10 cm.
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Additional comment
You may recognize the diagonal and the given sides form a 3-4-5 right triangle with a scale factor of 2. The diagonal will be the hypotenuse of a right triangle only if the parallelogram is a rectangle.