The length of the garden box would be 10ft if the width is 6ft.
The circumference of the top of the cake is
in.
It sounds like the baker is trying to line the circumference with cherriesto fit as many as possible along the border, like in the picture I've attached below.
This comes down to dividing the cake's circumference by the diameter of each cherry:

or about 39 cherries, making the answer D.
Y = 54.
This is really complicated to explain, but since x is 36 and the angle on the other side of the known angle is also 36, that makes y 54. Each pair of angles has to equal to 90 degrees.
Hope this helps!
I think this is y = 2/1x+1