Posted by lilman on .
I really need some help, I don't fully understand. Exspecially with fractions, don't know how to enter them on calculator.
1. What is the approximate volume of the sphere?
524 m³ (my choice)
1,000 m³
1,256 m³
1,570 m³
2. What is the approximate surface area of the sphere?
225 yd2
707 yd2
1,767 yd2 (my choice)
5,301 yd2
3. What is the approximate volume of the sphere if the surface area is 482.8 mm²?
998 mm³
1,126 mm³
2,042 mm ³
2,993 mm³
I don't understand this one.
4. What is the approximate surface area of the sphere?
342.3 km2
451.9 km2
903.4 km2
2,713 km2
Don't understand.
5. What is the approximate radius of a sphere whose volume is 1,349 cm³?
5.7 cm
6.9 cm
11 cm
14.7 cm
Don't understand.

surface area and volume 
Reiny,
you are dealing with two equations
1. surface area of sphere = 4π r^2
2. volume of sphere = (4/3)π r^3
notice all you need is the radius.
Since we cannot see your diagrams, #1, and #2 cannot be checked
3. given 4πr^2 = 482.8
r^2 = 482.8/(4π) = 38.42
r= √38.42 = 6.198
volume = (4/3)πr^3 = 997.53 , looks like a)
4.
you must have the radius given to you, just plug into the formula
5.
(4/3)πr^3 = 1349
r^3 = 1349/((4/3)π) = 322.05
r= (322.05)^(1/3) , the cube root of 322.05
= 6.85 (looks like b) )
fractions are really just divisions
e.g. 3/4 = 3 ÷ 4 = .75
you calculator should have a key for π
for powers look for key such as y^{x} or a variation of that
to do 322.05^(1/3) I entered
322.05
y^{x}
(1/3)
=
to get 6.85447... 
surface area and volume 
Hannah,
number 2 is wrong its b. 707 yd^2.

surface area and volume 
Hannah is right,
1. 524 m^3 (A)
2. 707 yd^2 (B)
3. 998 mm^3 (A)
4. 451.9 km^2 (B)
5. 6.9 cm (B) 
surface area and volume 
The Grinch,
I got a 5/5. Go Mariners!

surface area and volume 
anon,
"Hannah is right" was correct!

surface area and volume 
School,
"Hannah is right" Is 100% right!