Answer:
There were 8 total steps
Step-by-step explanation:
Okay, so we start in the middle.
-2 + 4 = 2. We're back in the middle.
2 - 3 = -1. One away from the middle.
-1 + 5 = 4. Now you're at the top.
4 x 2 = 8
Surface area of the cylinder = 816.4 sq. ft.
Solution:
Height of the cylinder = 21 ft
Diameter of the cylinder = 10 ft
Radius of the cylinder = 10 ÷ 2 = 5 ft
Use the value of
= 3.14
Surface area of the cylinder = 
Substitute the given values in the surface area formula, we get
Surface area of the cylinder 

ft²
Hence the surface area of the cylinder is 816.4 sq. ft.
420 would be the middle number.
Hoped I Could Help:)