In parallelogram ABCD, e is any point on AD, the area of triangle EFD is 4.5 square centimeters, and the area of triangle BEF is 7.5 square centimeters. How many square centimeters is the area of a triangle?

Solution:

Because △EFD and △BEF are equal in height, FD/FB=7.5/4.5=5/3.

If BC and AD are high at the intersection f, the ratio of the two heights is also 5/3.

Then the height of △EFD is 3/8 higher than that of parallelogram, and because ED/BE is 3/5.

So S△EFD/S△ABE9/ 16

So S△ABE=8

The beginning of junior high school is just a cloud. Just have fun in primary school. There is no need to set so many questions for yourself.

I took more than 500 junior high school exams (only more than 600).

Now I'm a sophomore, third in math, and 2 1 in the whole city.

I'm not a great man, I can only say that many things are troubled.