1. Volumes of Prisms & Cylinders Objectives: 1) To find the volume of a prism. 2) To find the volume of a cylinder.

2. Volume ►V►V►V►Volume – Is the space that a figure occupies. MMMMeasured in cubic units. ►c►c►c►cm3, in3, m3, ft3

3. Finding the volume of a Prism ► Prism – 2  parallel bases and faces are rectangles. Cross sections are congruent to the bases. What is a Cross section? Cross section?Cross section? Height (h) Area of Base (B) V = Bh Height of Prism Area of Base or Cross Section A = lw (Rectangle)

4. Finding the Volume of a rectangular prism ► The box shown is 5 units long, 3 units wide, and 4 units high. How many unit cubes will fit in the box? What is the volume of the box?

5. Find the Volume of the Prism 5in 3in 10in V = Bh = (3in 5in)(10in) = (15in 2 )(10in) = 150in 3 Area of Base B = lw

6. Discussion: What prism is this? Look at the Cross Section to determine. Why can’t you use l w h? Cross Section Cross Section 8in 10in V = Bh = ½bh h = ½(8in) __ (10in) = (12in 2 ) (10in) = 120in 3 3in

7. Now work on this prism! It’s tricky so be careful. 20m 29m 40m V = Bh = ½bh h = ½(20m)__ (40m) = 210m 2 40m = 8400m 3 Height of the base: a a 2 + b 2 = c 2 a 2 + 20 2 = 29 2 a = 21 Triangle 21

8. Volume of a Cylinder Video for help: YouTube YouTube r h V = Bh Volume of right cylinder Height of cylinder Area of base or cross section: (Circle) A =  r 2

9. Ex.4: Find the area of the following right cylinder. 16ft 9ft V = Bh =  r 2 h = 3.14(8ft) 2 (9ft) = 200.96ft 2 (9ft) = 1809.6ft 3 Area of a Circle

10. Ex.5: Find the volume of the following composite figure. Half of a cylinder: V c = Bh =  r 2 h =  (6in) 2 (4in) = 452in 3 = 452/2 = 226in 3 12in 4in 11in Volume of Prism: V p = Bh = (11)(12)(4) = 528in 3 V T = V c + V p = 226in 3 + 528in 3 = 754in 3

11. What have we learned?? Volume of a prism or a cylinder: V = Bh Capitol “B” stands for area of the base. Composite Figures: Made up of two separate solids.