90 degrees converted to radians is pi/2 or π/2 radians.
Answer:
Surface area = 663π in².
Volume = (676/3)π in² ≈ 225.33 π in²
Explanation:
1) We know the radius and the lateral area.
2) With the radius you can find the areas of the top and the bottom.
For that, you use the formula:
area of the top = area of the bottom = π r²
∴ π (13 in)² = 169π in² (each)
3) Then, the surface area is the sum of the lateral area and the two bases (top and bottom)
surface area = lateral area + bottom area + top area = 325π in² + 2×169π in² = 663π in².
3) You can also find the height of the cylinder.
Use the formula: lateral area = 2π r h
∴ h = lateral area / [2 π r]
⇒ h = 325 π / [ 2π (13) ] = 12.5 in
4) With the height you can find the volume.
Use the formula: V = (4/3) π r³
∴ V = (4/3) π (13 in)³ = (676/3)π in² ≈ 225.33 π in²
Answer:
C. 4x = 12
Step-by-step explanation:
You and three friends= you + 3 friends=4 people
Pizza= 12 pieces
Each person eats equal pieces of pizza
x= number of pieces each person ate
Equation
4x=12
Divide both sides by 4
x=12/4
=3
x=3
Therefore, each person ate 3 pieces of pizza each
Check:
4x=12
4(3)=12
12=12
Answer:
πr²= 12.56
r²=12.56/3.14 = 4
r= 2
therefore , diameter = 2r = 2×2= 4 mm
