the formula for the area of a triangle is
[tex]A=b\cdot\frac{h}{2}[/tex]
then if we have a right triangle it would look like this
in a right triangle the base and the heigth are represented by the legs
using the leg given and the area we can find the other leg
[tex]\begin{gathered} A=\frac{b\cdot h}{2} \\ 10=\frac{4\cdot x}{2} \\ 2\cdot10=4\cdot x \\ 4x=20 \\ x=\frac{20}{4} \\ x=5 \end{gathered}[/tex]
the length of the other leg is 5 cm.
