Bunuel wrote:
A dam has the dimensions indicated in the figure. Find the area of this isosceles trapezoid.
(A) 1300
(B) 1560
(C) 1400
(D) 1440
(E) It cannot be determined from the information given.
Attachment:
The attachment 2018-03-08_1321.png is no longer available
When calculating areas, it is very useful to divide a complex shape into simpler ones.
This is an Alternative approach.
Since our trapezoid is isosceles, the two triangles on the sides are identical and have equal bases.
So, each has a base of (70 - 50)/2 = 10
Using the Pythagorean triplet 5-12-13, we know that the height of each triangle is 24.
So, our total area is (square + 2 triangles) = 50*24 + 10*24/2 + 10*24/2 = 60*24 = 1440
(D) is our answer.
Attachments
trapezoid.png [ 9 KiB | Viewed 594 times ]
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