Answer: [tex]SA=117.2\ in^2[/tex]
Step-by-step explanation:
You need to remember the following:
1. The area of a rectangle can be calculated with the following formula:
[tex]A_r=lw[/tex]
Where "l" is the length and "w" is the width.
2. The area of a triangle can be calculated with the following formula:
[tex]A_t=\frac{bh}{2}[/tex]
Where "b" is the base and "h" is the height.
Use those formulas to find the area of each face.
Area of the rectangle
[tex]A_r=(10\ in)(4\ in)=40\ in^2[/tex]
Area of two triangles
There are two equal triangles. Each one has a base of 10 inches and a height of 5 inches. Then, their areas are equal:
[tex]A_{t1}=A_{t2}=\frac{(10\ in)(5\ in)}{2}=25\ in^2[/tex]
The areas of the other two triangles (which are equal) are:
[tex]A_{t3}=A_{t4}=13.6\ in^2[/tex]
Adding the areas of the faces, you get that the surface area of the rectangular pyramid is:
[tex]SA=40\ in^2+25\ in^2+25\ in^2+13.6\ in^2+13.6\ in^2\\\\SA=117.2\ in^2[/tex]
