Thursday, February 23 rd
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Transcript of Thursday, February 23 rd
Thursday, February 23rd • Please complete warm up and write down the
Homework • Take out homework (Prism worksheet)
WARM UPThe length of a rectangle is 14 in, the width 6 in, and the height 3 in. 1. Find the Volume
2. Find the surface Area
Joke of the Day What bird is
good at making bread?
A “dough dough”
Homework Answers
Think, Pair, Share
Goal for today
Volume and Surface Area
CYLINDERS
How would you describe:
Net
Of a Cylinder?
Circle Review
A line segment with one endpoint at the center of the
circle and the other endpoint on the circle is a radius (plural: radii). It is half the diameter
CenterRadius
A diameter is a line segment that passes through the center of the circle and has both endpoints on the circle.
The length of the diameter is twice the length of the radius.
CenterRadius
Diameter
The distance around a circle is called the circumference.
CenterRadius
Diameter
Circumference
The formula for the circumference of a circle is C = d, or C = 2r.
Circumference
tttttttttttt
Area
Part 1: Surface Area
1. Using a Net
2. Using a Formula
Nets for Cylinder
Cylinders- the net for a cylinder is made of two congruent circles, and one rectangle.
•The circumference of the circle is the
length of the rectangle
Just WatchArea of Circle:
πr²3 x 5²3 x 2575
2 circles: 75 x 2 = 150
Area of Rectangle: L x WLength= circumference Length= 2πr Length= 2 x 3 x 5 Length = 6 x 5 Length = 30 Area =30 x 10Area = 3002 Areas=600
600 + 150=750
#1 Try Together
Area of 2 Circles:
Area of Rectangle:
#2 You TryArea of 2 Circles:
Area of Rectangle:
#3 You Try
Area of 2 Circles:
Area of Rectangle:
Surface Area with Formulas
SA= 2 πr² + 2πrhSA=__________+__________+__________
SA=__________+__________+__________
SA=__________+__________+__________
SA=_________
#1 Try Together
SA= 2 πr² + 2πrhSA=__________+__________+__________
SA=__________+__________+__________
SA=__________+__________+__________
SA=_________
#2 Try Together
SA= 2 πr² + 2πrhSA=__________+__________+__________
SA=__________+__________+__________
SA=__________+__________+__________
SA=_________
#3 You Try
SA= 2 πr² + 2πrhSA=__________+__________+__________
SA=__________+__________+__________
SA=__________+__________+__________
SA=_________
#4 You Try
Part 2: Volume
To find the volume of a cylinder, you can use the same method as you did for prisms: Multiply the area of the
base by the height.volume of a cylinder = area of base height
The area of the circular base is r2, so the formula is V = Bh = r2h.
Write the formula.
Replace with 3, r with 4, and h with 7.Multiply.V 336
V = r2h
V 3 42 7
The volume is about 336 ft3.
JUST WATCH
10 cm ÷ 2 = 5 cm Find the radius.
Write the formula.
Replace with 3, r with 5, and h with 11.Multiply.V 825
V = r2h
V 3 52 11
The volume is about 825 cm3.
#1 TRY TOGETHER
Multiply.V 540
The volume is about 540 ft3.
6 ft
5 ft
Write the formula.
Replace with 3, r with 6, and h with 5.
V = r2h
V 3 62 5
#2 YOU TRY
Multiply.V 288
8 cm ÷ 2 = 4 cm
The volume is about 288 cm3.
Find the radius.
8 cm
6 cm
Write the formula.
Replace with 3, r with 4, and h with 16.
V = r2h
V 3 42 6
#3 YOU TRY
3-2-1 Summary
3 things you learned
2 things you still need practice on
1 Which way do you like finding surface area: net or formula