2 years ago

the formula for the area of a circle is A pi r^2 what is the radius of a circle with an area of 400 pi cm^2

Mathematics

1 answer:

Bogdan [553]2 years ago

4 0

Answer: 20 cm

Step-by-step explanation: Isolate the variable by dividing each side by factors that don't contain a variable.

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Kendra has $6.00 in dimes and quarters. If she has 2 times as many quarters as dimes, how many of each coin does she have?

r-ruslan [8.4K]

Make a system of equations.

$\sf0.10d+0.25q=6$
$\sf~q = 2d$

Plug in 2d for 'q' in the first equation:

$\sf0.10d+0.25q=6$

$\sf0.10d+0.25(2d)=6$

Multiply:

$\sf0.10d+0.50d=6$

Combine like terms:

$\sf0.60d=6$

Divide 0.60 to both sides:

$\sf~d=10$

Now plug this into any of the two equations to find 'q':

$\sf~q = 2d$

$\sf~q = 2(10)$

$\sf~q = 20$

So she has 10 dimes and 20 quarters.

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3 years ago

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3 years ago

True or False?In Exercise,determine whether the statement is true or false given that f(x) = In x.if it is false,explain why or

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