There is a square whose side is 10√2 cm. If a certain length ‘a’ decreases from each vertex, will be formed in each corner isosceles right triangle by removing them will leave a regular octagon. The find the value of ‘a’?
1
8√2(√2 + 1)
2
10(2 - √2) cm
3
10(√2 - 1) cm
4
10√2(√3 - 1) cm