We know that
volume of a sphere=(4/3)*pi*r³----> (r/3)*(4*pi*r²)
and
surface area of sphere=4*pi*r²
so
the volume of a sphere=(r/3)*surface area of sphere
therefore
if r=3
volume of a sphere=(3/3)*surface area of sphere
volume of a sphere=surface area of sphere
if r> 3
the term (r/3) is > 0
so
volume of a sphere > surface area of sphere
if r<3
the term (r/3) is < 0
so
volume of a sphere < surface area of sphere
examples
1) for radius r=3 units
volume of a sphere=(4/3)*pi*3³----> 113.04 unit³
surface area=4*pi*3²----> 113.04 units²
volume is equal to surface area
2) for radius r=10 units
volume of a sphere=(4/3)*pi*10³----> 4186.67 unit³
surface area=4*pi*10²----> 1256 units²
volume is > surface area
3) for radius r=2 units
volume of a sphere=(4/3)*pi*2³----> 33.49 unit³
surface area=4*pi*2²----> 50.24 units²
volume is < surface area
Since no value is given to Eva, we'll call her x. Justin, then, is 7.50+x. That leaves Emma, who would be Justin (7.50+x) -12. If we add them all together we get 63. So our equation is
x + (7.50+x) + (7.50+x)-12 = 63
Combine like terms
x+x+x + 7.50+7.50-12 = 63
3x + 3 = 63
3x = 60
x = 20
Since we said Eva is x then Eva has 20 dollars.
Justin is 7.50 + x so 7.50+20=
$27.50
Emma is Justin - 12 so 27.50-12= $15.50
Let's check our answer...
15.50+27.50+20 = 63
63=63
It checks!
Answer:
7f
r = ----------- - 4
z
Step-by-step explanation:
I will assume that you meant:
7f
z = ------------
r + 4
Solve for r. Start by interchanging z and (r + 4):
7f
r + 4 = -----------
z
Now subtract 4 from both sides. This isolates r:
7f
r = ----------- - 4
z
The answer is B because 26-2 is 24 and 24-3 is 21 and 21/7 is 3 therefore x=3
Answer:
Step-by-step explanation:
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