636cm.
This can be found with the Pythagorean Theorem which will give you a side length of 4.5

meters, which rounds to roughly 636cm.
Answer:
It becomes 30
Step-by-step explanation:
When you double a number, it’s increases to two of itself .
So double of 15 means 15 x 2
= 30
(50 x 2) + (40 x 2) = 180 yards x 3 = 540 feet of fence needed. 540 / 5 = 108. He will need 108 pieces of fencing