Mathematics - Pythagorean theorem

in previous article, we cover why monster take 7 cells to the right is same amount of time moving 5 cells diagonally

reason ? Pythagorean theorem
A² + B² = C²
since monster is moving diagonally (45º), A = B
5² + 5² = C²
2(25) = C²
50^½ = C
C = 7.07106...

so, what if it is the opposite ?
let's say I have 30 cells to the right, and I want to know how many cells needed to travel diagonally in the same amount of time
the formula is
2(A²) = C²
where C = 30
2(A²) = 30²
2(A²) = 900
A² = 450
A =  21.21320....