step 1
Find out the area of the triangle
[tex]A=\frac{1}{2}*b*h[/tex]
where
b=5 units
h=4 units
substitute
[tex]\begin{gathered} A=\frac{1}{2}*5*4 \\ A=10\text{ units}^2 \end{gathered}[/tex]
step 2
The formula to calculate the area of a rectangle is given by
[tex]A=L*W[/tex]
where
Remember that the area of the triangle is on half of the rectangle
area of the triangle is 10 square units
that means
The area of the rectangle is 20 square units
so
we have
A=20 unit2
L=5 units
W=?
substitute in the formula
20=(5)*(W)
solve for w
w=20/5
w=4 units
