7 1/7 = 100/14 and 2 1/2= 35/14. 100 - 35 =65 so the answer is 65/14.
Just multiply each number on the right by 12 since each cake has 12 pieces. if there were 2 cakes then there are 24 pieces just keep doing that all the way down
(6.5)(2.5)
It’s in the middle of two numbers that’s why the .5 is there
Area of the Rectangle = 
Area of a Triangle = 
Take both areas and subtract them:

This means shaded area = 68 in^2
Hope this helps!
I believe that you would have to divide by four.