The square root of 81 is 9
Answer:
k = 11
Step-by-step explanation:
Given the points are collinear then the slopes between consecutive points are equal.
Using the slope formula
m = 
with (x₁, y₁ ) = (5, 1) and (x₂, y₂ ) = (1, - 1)
m =
=
= 
Repeat with another 2 points and equate to 
with (x₁, y₁ ) = (1, - 1) and (x₂, y₂ ) = (k, 4)
m =
, then
=
( cross- multiply )
k - 1 = 10 ( add 1 to both sides )
k = 11
Answer:
The surface area is 3140 feet².
What is Surface Area?
Surface area is the amount of space covering the outside of a three-dimensional shape.
Given that:
Diameter = 20 feet
radius = 20 ÷ 2 = 10 feet
Now, Surface area will be,
=2πr²+ 2πrh
= 2 × 3.14 × (10)² + 2 × 3.14 × 10 × 40
= 6.28 × 100 + 6.28 × 400
= 628 + 25.12 × 100
= 628+ 2512
= 3140 feet²
hence, the surface area is 3140 feet².
Step-by-step explanation: