Math 9 Midterm Review: Surface Area

Question: Jerrys bedroom is square. He has a desk in his bedroom which has an area of 10000 cm2. The area of the bedroom is sixteen  times the area of the desk. What is the side length of the bedroom.

My First Answer: 10000 x 16 =160000/2 =80000

Correct Answer: Instead of dividing 160000 by 2 I should’ve found the square root of 160000=400

Website: http://www.mathopenref.com/squarearea.html       http://www.factmonster.com/ipka/A0932229.html

 

 

Question: What is the total surface area of the rectangular prism. 3a, a,2a.

My First Answer:

(2a x a)  + (3a x a) + (2a x 3a)

= 2a2 + 3a2 + 6a2

= 11a2

Correct Answer: Formula 2(wl + hl +hw)

=2(2a x a) 2(3a x a) 2(2a x3a)

= 4a2 + 6a2 + 12a2

=22a2

Video:

Website:  http://www.aaamath.com/geo79_x9.htm

 

 

 

 

 

 

 

 

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