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:
4, 13, 28, 49
Step-by-step explanation:
1st term = 3 × (1)² + 1 = 4
2nd term = 3 × (2)² + 1 = 13
3rd term = 3 × (3)² + 1 = 28
4th term = 3 × (4)² + 1 = 49
Yes I sure did hang the picture what about it
<span>1. 5564÷91
I know that 9 * 6 = 56
5564 rounds to 5600
91 rounds to 9
Since 56/9 = 6, then 5600/90 is the same as 560/9 = 60
The estimate is 60
2. </span><span>5391÷25
5391 sounds to 5400
25 is 1/4 of 100.
That means when you divide by 25, you can divide by 100 and multiply by 4.
5400/100 = 54
54 * 4 = 216
Estimate: 216
3. </span><span>explain how to estimate 498÷12
48/12 = 4
498 is little more than 480, so 498/12 is little more than 40
4. </span><span>which is the closest estimate for 2130÷ 33
A.7 B.17 C.70 D.700
2130/33
Round off the numerator and denominator to
2100/30
Reduce the fraction
210/3
Since I know that 21/3 = 7, then 210/3 = 70
Estimate: 70
</span>
Answer:
2.8 hours
Step-by-step explanation:
Distance = rate * time
If the west-bound train travels at a rate of 80 mph for t hours, then the distance it travels is 80t.
If the east-bound train travels at a rate of 90 mph for t hours, then the distance it travels is 90t.
The distance between the trains after t hours is 476; therefore, the distance of the west-bound train plus the distance of the east-bound train equals the total distance between them, 476:
80t + 90t = 476 and
170t = 476 so
t = 2.8 hours