40 inches because a rectangle has 2 sets of parallel lines and if the width and length are 10 then you just have to add up all the sides.
There are 72 boys. 7:6 = 84:?, divide 84 by 7, you get 12. Multiply 6 by 12 to get the answer.
(predicted value - exact value)/exact value * 100
(31 - 34)/34 * 100 = 8.8%
you would change the denominators to the least common multiple, in this case, 12. then you would change the fractions to 8/12, 14/12, and 7/12. you would add those, and get 29/12. divide 29 by 12, and get 2. add the rest to get 2 5/12.
