We know that
• The height of the triangle is 4 feet.
,• The area must be at least 10 square feet.
Using the given information, we express the following inequality. Remember that the area of a triangle the semi-product of the base and height.
[tex]\frac{b\cdot4}{2}\ge10[/tex]Then, we solve for b.
[tex]\begin{gathered} 2b\ge10 \\ b\ge\frac{10}{2} \\ b\ge5 \end{gathered}[/tex]