Answer
5
Work Step by Step
To calculate distance between given points, i. e. origin (0, 0) and (3,-4), we will use distance formula-
r = $ \sqrt { (x_{2} - x_{1}) ^{2} + (y_{2} - y_{1}) ^{2}}$
= $ \sqrt { (3 - 0) ^{2} + (-4 - 0) ^{2}}$
= $ \sqrt { (3) ^{2} + (-4) ^{2}}$
= $ \sqrt {9 +16}$
= $ \sqrt {25}$
= 5
