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.).
90 = k*15
constant of proportionality = 80 / 15 = 6 Answer
Answer:
9 beads are purple
Step-by-step explanation:
we know that
To find out how many beads are purple, multiply the total beads by the fraction of the beads that are purple
so

therefore
9 beads are purple
Another way to solve the problem is convert the fraction in percentage
we have

so
If the total are 18 beads
50% is 9 beads
therefore
9 beads are purple
Answer:
<h2>4 + 3x</h2>
Step-by-step explanation:
The product of three and a number x: 3 · x = 3x
The sum of four and the product of three and a number x:
4 + 3x

Multiply 50 by 0.90 because you take a discount of 10% off. 1.00 = 100% 0.10 = 10% 0.01 = 1% if you multiply 50 by 0.10 instead you get the amount that is discounted instead of the new selling price.