Answer: 346.19cm²
Step-by-step explanation:
π= 3.14
Divide 21 (the diameter) by 2 to get the radius( it 's half of the diameter). so the radius is 10.5
Area= πr²
= 3.14x10.5x10.5
= 346.185
So next round up the value you got to the nearest tenth, so when u round up to the nearest tenth you get 346.19
Answer:
2
Step-by-step explanation:

The approximate difference between Calvin and Makayla's number of years of money invested is 2 years.
<h3>What is compound interest?</h3>
Compound interest is the amount charged on the principal amount and the accumulated interest with a fixed rate of interest for a time period.
The formula for the final amount with the compound interest formula can be given as,

Here,
is the final amount (principal plus interest amount) on the principal amount of
with the rate of
in the time period of
.
Calvin deposits $400 in a savings account and Interest rate is 5 present compounded monthly.
As the final amount Calvin has $658.80 in c years. Thus the monthly compound interest can be given as,

Now Makayla deposits $300 in a different savings account that accrues 6% interest compounded quarterly. The final amount she gets is $613.4 in m years. Thus,

Thus, the approximate difference in the number of years that Calvin and Makayla have their money invested is 2 years.
Learn more about the compound interest here;
brainly.com/question/24274034
<h3>
Answer: 28k+68</h3>
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Work Shown:
7(8+4k)+12
7*8+7*4k+12 ..... distributive property
56+28k+12
28k+56+12
28k+68