Answer: The answer is 314.28 cm² (approx.).
Step-by-step explanation: Given that an engineer is going to install a new water pipe. The diameter of this circular pipe is, d = 20 cm.
We need to find the area 'A' of the circular cross-section of the pipe.
Given, diameter of the circular section is

So, the radius of the circular cross-section will be

Therefore, cross-sectional area of the pipe is

Thus, the answer is 314.28 cm² (approx.).
Answer: 6.3
Step-by-step explanation:
The formula for geometric mean is given as :
G.m = 
Therefore , the geometric mean between 4 and 10 will be :
G.m = 
= 
= 2
= 6.3
Answer:
B. 6 units
Step-by-step explanation:

I am joyous to assist you anytime.
Answer: 5.3571
Step-by-step explanation:
The formula used to calculate direct proportion is: y = kx
We will find the constant of proportionality when y=10 and x=5.6. This will be:
y = kx
10 = 5.6k
k = 10/5.6
k = 1.7857143
The value of y when X=3 will be:
y = kx
y = 1.7857143 × 3
y = 5.3571