Note that a squared pyramid has a square base & 4 equal triangles.
To find the lateral the lateral area you calculate the area of the 4 equal triangles and to find the surface area (total Area) you add the area of the base:
Area of each triangle = side (5) x slant (9) and you divide by 2
==>Aera of 1 triangle = (9x5)/2 = 45/2 & for the 4 triangles
Lateral area = (45/2) x 4 = 90 in²
Now the base area (square) = 5 x 5= 25 in²
so the surface area = 90+25 = 115 in² (answer a)
Step-by-step explanation:
this is totally simple.
the formula for the area of a circle (as you can find with any search on the internet in seconds) :
A = pi×r²
r is the radius.
and once you understand even the most basics of a circle, you know that the radius is half of the diameter.
so, in our case, r = 6/2 = 3 m
the area of the circle is therefore
pi×r² = pi×3² = pi×9 m²