Cathy saved $320 last month. this month, she saved $377.60. what is the percent increase for the amount of money cathy saved?

At the first you should calculate the difference amount between two month:
$ 377.60-$320=$57.60
And then you divide $57.60 by $ 320
like $57.60/ $320= 0.18=18%
So 18% is the answer 

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You must find the surface of the block therefore 98187 dived by 5628 = 583m squared