Try this beautiful problem from Geometry: Side of Square.
Square $ABCD$ has side length $10$. Point $E$ is on $\overline{BC}$, and the area of $\triangle ABE$ is $40$. What is $BE$?
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Geometry
Square
Triangle
Answer: $8$
AMC-10A (2013) Problem 3
Pre College Mathematics
Given that Square $ABCD$ has side length $10$ and area of $\triangle ABE$ is $40$.we have to find out length of \(BE\) where \(E\) is the point on \(BC\). we know area of the \(\triangle ABE=\frac{1}{2} AB.BE=40\)
Can you find out the side length of \(BE\)?
Can you now finish the problem ..........
\(\triangle ABE=\frac{1}{2} AB.BE=40\)
\(\Rightarrow \triangle ABE=\frac{1}{2} 10.BE=40\)
\(\Rightarrow \triangle ABE=\frac{1}{2} 10.BE=40\)
\(\Rightarrow BE=8\)