If the side of the mirror is A Inches then the length of the diagonal is A*√2 Inches.
A√2 = 20
A = 10*√2 = 14.14
Perimeter of the mirror = 4A = 4*14.14 = ~57 = ~60.
square mirror
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neelgandham
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Anil Gandham
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alex.gellatly
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For this question it's important to remember three things:grandh01 wrote:If a square mirror has a 20-inch
diagonal, what is the approximate
perimeter of the mirror, in inches?
(A) 40
(B) 60
(C) 80
(D) 100
(E) l20
1) The diagonal of a square is equal to x√2 when x=side of the square
2) √2 is approximately 1.41
3) The premier of a square is equal to 4x, when x=side of the square.
OK now, lets solve this thing:
So the diagonal is x√2= x*1.41 This is equal to 20. x*1.41 = 20
solve for x you get x=14 (plus some remainder, but this is an approximation question so I don't care about the remainder).
Now 14*4=56 (plus some remainder which would have been multiplied by 4, so obviously our answer is larger than 56)
The closest answer is 60. Choose B
A useful website I found that has every quant OG video explanation:
https://www.beatthegmat.com/useful-websi ... tml#475231
https://www.beatthegmat.com/useful-websi ... tml#475231
