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3 years ago

The sum of the areas of two circles is 80 pi

1 answer:

5 0

The area of a circle is A = πr^2. We let A1 And A2 the areas of the circles and r1 and r2 the radius of each, respectivley.

A1 + A2 = 80π
Substitute the formula for the area,
π(r1)^2 + π (r2)^2 = 80π

From the statement, we know that r2=2(r1).

<span>π(r1)^2 + π (2 x r1)^2 = 80π
</span>We can cancel π, we will have

5 x (r1)^2 = 80
Thus,

r1 = 4 and r2 = 8

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MAKE SURE TO SHOW YOUR WORK (please)

creativ13 [48]

Answer:

9.11 x 10^-28

Step-by-step explanation:

if you divide 9.11 x 10^-28 by 1.67 x 10^-24 you get .000546

if you divide 1.67 x 10^-24 by 9.11 x 10^-28 you get 1,833

therefore, 1.67 x 10^-24 is 1833 times greater than the other value

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2 years ago

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Softa [21]

Answer:

the first one

Step-by-step explanation:

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3 years ago

Please help!!!!!! Solve for x:

nordsb [41]

A
Explanation: You want to get x by itself. So add +7 to -7 to cancel it out, do the same thing to 4.
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2 years ago

Find the value of this expression if x=5

Nastasia [14]

so, uh, i think the answe is actually 5. Since 5^2 is 25, minus 5 is 20, and 5 minus 1 is 4, 20 divided by 4 is 5. i hope that helps.

4 0

2 years ago

On Naomi's cell phone plan, the amount she pays each month for international text messages is proportional to the number of inte

Lostsunrise [7]

A) The constant of proportionality in this proportional relationship is $k = \frac{y}{x}$

B) The equation to represent this proportional relationship is y = 0.2x

<h3><u>Solution:</u></h3>

Given that,

The amount Naomi pays each month for international text messages is proportional to the number of international texts she sends that month

Therefore,

This is a direct variation proportion

$\text{ amount Naomi pays each month } \propto \text{ number of international texts she sends that month}$

Let "y" be the amount that Naomi pays each month

Let "x" be the number of international texts she sends that month

Therefore,

$y \propto x$

y = kx -------- eqn 1

Where, "k" is the constant of proportionality

Thus the constant of proportionality in this proportional relationship is:

$k = \frac{y}{x}$

<em><u>Last month, she paid $3.20 for 16 international texts</u></em>

Therefore,

y = 3.20

x = 16

Thus from eqn 1,

$3.20 = k \times 16\\\\k = \frac{3.20}{16}\\\\k = 0.2$

Substitute k = 0.2 in eqn 1

y = 0.2x

The equation would then be y = 0.2x

8 0

2 years ago