Answers

2014-10-27T19:57:24+08:00
Let 's' be the length of one side of the bigger square cardboard.
since it is square we can say that its area is A=s²
since 3cmx3cm was cut out of it and the remaining area is 20cm² then you'll have the expression as:
s² - 3² = 20
getting the value of s you'll have:
s² - 3² = 20
s² - 9 = 20
s² = 20 + 9
s² = 29
s = √29 cm
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