Question

determine the surface area. 2.5m 80cm

Explanation:

Step1: Convert units

First, convert 80 cm to m. Since 1 m = 100 cm, then 80 cm=0.8 m.

Step2: Calculate base - area

The base of the pyramid is a square. The area formula for a square is $A_{base}=s^{2}$, where $s = 0.8$ m. So $A_{base}=0.8^{2}=0.64$ $m^{2}$.

Step3: Calculate area of one triangular face

The area formula for a triangle is $A_{\triangle}=\frac{1}{2}bh$, where the base $b = 0.8$ m and the slant - height $h = 2.5$ m. So $A_{\triangle}=\frac{1}{2}\times0.8\times2.5 = 1$ $m^{2}$.

Step4: Calculate total surface area

A square - based pyramid has 4 triangular faces and 1 square base. The total surface area $A = A_{base}+4A_{\triangle}$. Substitute the values: $A=0.64 + 4\times1=4.64$ $m^{2}$.

Answer:

$4.64$ $m^{2}$