The figure below shows AB = 2 units and BD = 5 units
If the area of triangle ADE is 70 square units, what is the area of the trapezoid BCED?

Question

The figure below shows AB = 2 units and BD = 5 units
If the area of triangle ADE is 70 square units, what is the area of the trapezoid BCED?

anonymous · Answer

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anonymous · Answer

there are a few ways to do this one. 

If we take the area of ade(70) and subtract the area of ABC then we have the area of the trapezoid.

anonymous · Answer

A fact that you need to know to do this problem: If two similar triangles have a scale factor of a : b, then the ratio of their areas is a2 : b2.

anonymous · Answer

So, you can see that these two triangle have a scale factor of 2:5. Therefore the ratio of their areas is simply 2^2 / 5^2 = 4/25
Use that to find the area of the smaller triangle. Subtract the area of the small triangle form the large triangle and you're doneso =)
Ask me any questions that come up.

anonymous · Answer

You explained that really well, I appreciate you're help :)

anonymous · Answer

Well golly, aren't you pleasant to help? =D

anonymous · Answer

Haha I guess so c: