Ok so, when working to find if a fraction is equal to another you must know what it is cut down by. So 6 / 2 = 3. Now let's break down 7 by 2. It is 3.5 that is not four. So no 6/7 so not equal to 3/4.
3.14((4^2)+(4)(2))
3.14(16+8)
3.14(24)
=75.36
You just want to plug in the values of a and b into the equation and solve using order of operations. Hope this helps!