Since all 4 sides of the pyramid are the same we just need to find out the area of one face then multiply it by 4. The formula to figure out the area of a triangle is base x height ÷ 2. Now we just need to plug in the numbers.
Surface Area=bxh÷2
SA=7.2x6.2÷2
SA=44.64÷2
SA=22.32
Now that we have the area of one face we need to multiply it by 4.
22.32 x 4 = 89.32
The closest answer to 89.32 would be 88.3cm2 so the answer is B.
