Which of the following fractions is not simplest form 4/15

7/10

9/12

3/4

Based on what i know about mean, this doesn't add up.

What two criteria are needed for triangles to be similar

Afarmer has a large field that is x feet in length. he wants to fence in a rectangular section in the middle of the field , leaving a length of 100 feet of open field behind each end of the fenced rectangle.he also wants the width of the fenced-in space to be 100 feet less than its length. find the expressions to represent the length and width of the fenced section of the field