Answer:
28.258mm
Step-by-step explanation:
A semi circle is half of a circle, so we will divide it by 2 after finding the area.
Formula for finding semi circle = pi x radius ÷ 2
Formula for radius = diameter ÷ 2
Radius = 36 ÷ 2 = 18mm
Semi circle = 3.14 or 22/7 x 18 = 56.57
56.57 ÷ 2 = 28.285
Note: I don't have a calculator with me right now, so you might want to consider typing out pi x 18 ÷ 2 on a calculator since my answer might be wrong because the answer has endless decimals.
Answer:
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Step-by-step explanation:
75% = 3/4
3/4 of 180 = 135
Let n = number of nickels, and p = number of pennies.
The number of coins is 25, so we get this equation.
n + p = 25
The value of the coins is 0.05 per nickel, and 0.01 per penny.
0.05n + 0.01p = 0.73
Now you have a system of equations.
n + p = 25
0.05n + 0.01p = 0.73
Solve the first equation for n:
n = 25 - p
Now substitute into the second equation.
0.05(25 - p) + 0.01p = 0.73
1.25 - 0.05p + 0.01p = 0.73
-0.04p = -0.52
p = 13
There were 13 pennies.
Now we substitute 13 for p in n + p = 25 to find out the number of nickels.
n + 13 = 25
n = 12
There are 13 pennies and 12 nickels.
Check: 13 pennies and 12 nickels does total 25 coins.
13 * 0.01 + 12 * 0.05 = 0.13 + 0.60 = 0.73
The value is $0.73.
Our answer is correct.
