Answer:
When all side faces are same
surface area = lw + 1/2 × perimeter × slant height.
When the side faces are different
surface area = base area + lateral area
Explanation:
The question you ask is the formula one can use to calculate the surface area of a rectangular pyramid.
The base of a rectangular pyramid is rectangular. The picture below shows how a rectangular pyramid looks like .
The surface area of the rectangular pyramid includes the area of the base and areas of all the triangular faces. This simply implies the area of the rectangular base and the area of each triangular faces. Mathematically, it can be represented below.
The base area(rectangle) = length × width = lw
Area of a triangle = 1/2 × base × height = 1/2bh
Therefore, if all the faces of the triangle are the same(regular pyramid) the total surface area will be
surface area = lw + 1/2 × perimeter × slant height.
Note the triangular faces are 4 in numbers.
If all the sides of the triangle are different the surface are will be
surface area = base area + lateral area
We have to add the triangular faces individually for an irregular pyramid.