formula for surfacea area of rectangular pyramid

1 answer

The surface area \( S \) of a rectangular pyramid can be calculated using the following formula:

\[ S = A_b + A_l \]

Where:

  • \( A_b \) is the area of the base (the rectangle).
  • \( A_l \) is the total area of the four triangular faces (lateral surface area).
  1. Calculate the area of the base \( A_b \): If the base has length \( l \) and width \( w \): \[ A_b = l \times w \]

  2. Calculate the lateral surface area \( A_l \):

    • Let \( h \) be the height of the pyramid (the perpendicular height from the apex to the base) and \( s_1 \) and \( s_2 \) be the slant heights of the triangular faces:
    • There are two triangles with base \( l \) and height \( s_1 \), and two triangles with base \( w \) and height \( s_2 \).

    So the lateral area is given by: \[ A_l = \frac{1}{2} \times l \times s_1 + \frac{1}{2} \times w \times s_2 \]

Therefore, the total surface area becomes: \[ S = (l \times w) + \left(\frac{1}{2} \times l \times s_1 + \frac{1}{2} \times w \times s_2\right) \]

This formula allows you to calculate the surface area of a rectangular pyramid using the base dimensions and the slant heights of the triangular faces.