In the isosceles trapezoid ABCD, AD / / BC, assuming BC = 4, ad = 8, angle a = 45 degrees, the area of the trapezoid is calculated
Use the sum of the bottom and the top, multiply the height and divide by 2
Height means that AE is perpendicular to BC and AF is perpendicular to BC, because it is isosceles trapezoid,
So be plus FC will be equal to 8-4 = 4. Be = FC, so be = 2,
Because AC = EF, so AE = 2, understand the wave
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