Key Ideas Review:
1. Complete the chart below, using the first row as a sample. Show your answer to the nearest tenth.
*NOTE: The surface area for the triangle was supposed to be 1.5m (squared)
Square: A = l x w
= 10 x 10
= 100 cm (squared)
Rectangle: A = l x w
= 30 x 22.5
= 675 cm (squared)
Circle: A = pi x r squared
= pi x (15 x 15)
= pi x 225
= 706.9 cm (squared)
Rectangular Prism: A = 2(lw) + 2(lh) + 2(hw)
= 2(25 x 12) + 2( 25 x 12) + 2( 12 x 12)
= 2(300) + 2(300) + 2(144)
= 600 + 600 + 288
= 1488 cm (squared)
Cylinder: A = 2 [(pi)(r) squared] + 2 (pi)[( r x h)]
= 2 [(pi) (4 x 4)] + 2[ (pi) (4 x 15)]
= 2 (pi) (16) + 2 (pi) (60)
= 2 (50.3) + 2 (188.5)
= 100.6 + 377
= 477.6 cm (squared)
* NOTE: I rounded the answer for pi x 16 and pi x 60 to the nearest tenth which is why my answer is 0.1 higher.
Triangle: A = 1/2 b x h
= 1 x 1.5
= 1.5 cm (squared)
My Examples:
Square: One side of a box: 20 cm by 20 cm
A = l x w
= 20 x 20
= 400 cm (squared)
Rectangle: A wooden door: 35 cm by 23
A = l x w
= 35 x 23
= 805 cm (squared)
Circle: One side of a car tire: Radius of 17 cm
A = pi x r squared
= pi x (17 x 17)
= pi x 289
= 907.9 cm (squared) nearest tenth
Rectangular Prism: Math textbook: l= 7 cm w= 8 cm h= 5 cm
A = 2(lw) + 2(lh) + 2(hw)
= 2( 7 x 8) + 2(7 x 5) + 2(5 x 8)
= 2 (56) + 2(35) + 2(40)
= 112 + 70 + 80
= 262 cm (squared)
Cylinder: Hairspray Can: 13 cm high and 6 cm for radius
A = 2 [pi r (squared)] + 2 [pi (r x h)]
= 2 [pi (6 x 6)] + 2 [pi (6 x 13)]
= 2 (pi x 36) + 2 (pi x 78)
= 2 x 113.1 + 2 x 245
= 226.2 + 490
= 716.2 cm (squared)
*NOTE I rounded the answer for pi x 36 and pi x 78 to the nearest tenth.
Triangle: End of a Toblerone Package: 4 cm for base and 2.5 cm high
A = 1/2 b x h
= 2 x 2.5
= 5cm (squared)
Thank you for reading my blog and please don't forget to COMMENT !
Good job MaryJane. I like your colours and the way you did the chart. I didn't find any mistakes so congratz.
ReplyDeleteGOOD JOB MARYJANE ! I liked your use of colours and the way you gave real examples . Wonderful Job on the table , it is clear to see that you put in a lot of time and effort in making this blog post. Good Job Maryjane!
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