What is the length of the hypotenuse of a right triangle whose two sides are 6 and 8?

length^{2}= 6^{2}+ 8^{2}length^{2}= 36 + 64 = 100 length = 10

The formula for the length of a 2D vector
is the Pythagorean Formula.
Say that the vector is represented by
(x, y)^{T}.
Put the vector
with its tail at the origin.
Now make a triangle by drawing the two sides:

side_1 = (x, 0)^{T}side_2 = (0, y)^{T}.

The length of side_1 is x, and the length of side_2 is y, so:

length (x, y)^{T}= √( x^{2}+ y^{2})

In this formula, √ means the positive square root. We don't (of course) want the length to be negative.

What is the length of the vector represented by
( 4, 3 )^{T} ?