Use the dot product to find the magnitude of u. $\mathbf { u } = 24 \mathbf { i } - 28 \mathbf { j }$
A) $4 \sqrt { 85 }$
B) $\sqrt { 1358 }$
C) $2 \sqrt { 339 }$
D) $\sqrt { 1362 }$
E) $2 \sqrt { 341 }$

Question

Use the dot product to find the magnitude of u.   $\mathbf { u } = 24 \mathbf { i } - 28 \mathbf { j }$  
A) $4 \sqrt { 85 }$
B) $\sqrt { 1358 }$
C) $2 \sqrt { 339 }$
D) $\sqrt { 1362 }$
E) $2 \sqrt { 341 }$

Quizplus · Accepted Answer

The magnitude of a vector $\mathbf{u} = a\mathbf{i} + b\mathbf{j}$ is given by $\sqrt{a^2 + b^2}$. For $\mathbf{u} = 24\mathbf{i} - 28\mathbf{j}$, the magnitude is $\sqrt{24^2 + (-28)^2} = \sqrt{576 + 784} = \sqrt{1360} = 4\sqrt{85}$.

Use the Dot Product to Find the Magnitude of U u=24i−28j\mathbf { u } = 24 \mathbf { i } - 28 \mathbf { j }u=24i−28j

Use the Dot Product to Find the Magnitude of U $\mathbf { u } = 24 \mathbf { i } - 28 \mathbf { j }$