Physics: What is this equation? V = (V1^2 + V2^2) ^ 0.5

Its used in a solution, but I'm not sure what the purpose is.

Looks like vector analysis to me. If two vector forces, V1 and V2, are acting perpendicular to each other, then the resultant vector, V, can be found using the Pythagorean Theorem:

V = √[(V1)² + V2)²] = [(V1)² + (V2)²]^0.5.

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It is square root of (Sum of squares of two numbers v1 and v2)