How long should the wooden frame be (use 3.14 for pi)

C=2πr
The  C stands for circumference 
the π is Pi (3.14) 
and r is the radius (length of half a circle)

Since the sides are 10 ft you multiply that by 2 to get the length of both sides which gives you 20 feet. 

Then to find the circle, since both are half circles. You can just do the normal circumference equation and you will end up with the same answer.

For example in this problem: this problem gives you the diameter but you need the radius of the circle. C=2(π)(1.5)

C=9.42 < this is the circumference of the circle. 

Then you add the sides of the table which are 20 feet. 

So the final answer is 29.42 feet. 

In this problem it decreased 20%