What is the numerical value of the vector 3i+4j+5k . . .

Question : What is the numerical value of the vector 3i+4j+5k?

a) 3√2
b) 5√2
c) 7√2
d) 9√2

Doubt by Avani

Solution : 

The numerical value of a vector means the magnitude of a vector. 

Let A = 3i+4j+5k

A = √[(3)²+(4)²+(5)²]
A = √[9+16+25]
A = √[50]
A = √[2×25]
A = 5√2 

Hence, b) 5√2 would be the correct option.