Sphere = 3Dimensional Round Shape with All Surface Points Equidistant from Center
Basics
r = radius = distance from surface to center
d = diameter = distance all the way across sphere through its center
SA = Surface Area = area covering surface of sphere (measured in square units)
V = Volume = space occupied by sphere (measured in cubic units)
Formulas (Mathematics Formula Sheet)
SA = 4πr²
V = πr³
Formulas (NOT on Mathematics Formula Sheet)
r =
Question
A ball has a radius of 7 centimeters. What is its surface area?
Answer
196π square centimeters
Answer Process
SA = 4πr²
SA = 4 × π × 7² = 196π
Input  Display  Comment 
blinker  clears screen  
4 × π × 7  4*π*7²  SA = 4πr² 
196π  Answer  
Sphere 
Question
With reference to the question above, what is the surface area of the ball in decimal form?
Answer
615.7521601 square centimeters
Answer Process
See Toggle.
196π ⇔ 615.7521601
Input  Display  Comment 
blinker  clears screen  
4 × π × 7  4*π*7²  SA = 4πr² 
196π  
615.7521601  Answer (Toggle) 

Sphere 
Question
With reference to the question above, what is the area of the sphere to the nearest tenth?
Answer
615.8 square centimeters
Answer Process
See Rounding.
615.7521601 → 615.8
Question
A ball has a diameter of centimeters. To the nearest tenth of a square centimeter, what is its surface area?
Answer
660.5 square centimeters
Answer Process
r =
r = =
SA = 4πr²
SA = = = 660.5198554 after toggle = 615.8 after rounding
Input  Display  Comment 
blinker  clears screen  
1 2 × 14 1 2 
r =


r  
4 × π × 29 4  4*π*  SA = 4πr² 
660.5198554  Answer (before rounding) 

Sphere 
Question
A ball has a radius of 7 centimeters. To the nearest hundredth of a cubic centimeter, what is its volume?
Answer
1436.76 cubic centimeters
Answer Process
V = πr³
V = x π x 7³ = = 1436.75504 after toggle = 1436.76 after rounding
Input  Display  Comment 
blinker  clears screen  
4 3 × π × 7 3 
*π*7³  V = πr³ 
1436.75504  Answer (before rounding) 

Sphere 
Question
A ball has a diameter of centimeters. To the nearest hundredth of a cubic centimeter, what is its volume?
Answer
1596.26 cubic centimeters
Answer Process
r =
r = =
V = πr³
V = = =1596.256317 after toggle = 1596.26 after rounding
Input  Display  Comment 
blinker  clears screen  
1 2 × 14 1 2 
r =  
r  
4 3 × π × 29 4 3 
V = πr³  
1596.256317  Answer (before rounding) 

Sphere 
Practice – Questions
1. A model globe has a radius of 6 inches. What is its surface area?
2. With reference to Question 1, what is the globe’s surface area to the nearest tenth?
3. A model globe has a diameter of inches. To the nearest tenth of a square inch, what is its surface area?
4. A model globe has a radius of 6 inches. To the nearest hundredth of a cubic inch, what is its volume?
5. A model globe has a diameter of inches. To the nearest hundredth of a cubic inch, what is its volume?
Practice – Answers
1. 144π square inches
2. 452.4 square inches
3. 471.4 square inches
4. 904.78 cubic inches
5. 962.51 cubic inches