Answer
With $\hat{i}$ directed forward and $\hat{j}$ directed leftward, the resultant is $(5.00 \hat{\mathrm{i}}+2.00 \hat{\mathrm{j}}) \mathrm{m}$
The magnitude is given by the Pythagorean theorem:
$$\sqrt{(5.00 \mathrm{m})^{2}+(2.00 \mathrm{m})^{2}}=5.385 \mathrm{m} \approx 5.39 \mathrm{m} $$
Work Step by Step
With $\hat{i}$ directed forward and $\hat{j}$ directed leftward, the resultant is $(5.00 \hat{\mathrm{i}}+2.00 \hat{\mathrm{j}}) \mathrm{m}$
The magnitude is given by the Pythagorean theorem:
$$\sqrt{(5.00 \mathrm{m})^{2}+(2.00 \mathrm{m})^{2}}=5.385 \mathrm{m} \approx 5.39 \mathrm{m} $$