91Ó°ÊÓ

Solve \(\triangle A B C.\) \(a=8.5, \quad b=11.7, \quad c=13.1\)

Find the four fourth roots of \(-8+8 \sqrt{3} i\)

Solve \(\triangle A B C\) \(\gamma=73.01^{\circ}, \quad a=17.31, \quad c=20.24\)

Represent the complex number geometrically. $$(1+2 i)^{2}$$

Exer. 13-16: Show that the vectors are parallel, and determine whether they have the same direction or opposite directions. $$\mathbf{a}=\langle 6,18\rangle, \quad \mathbf{b}=\langle- 4,-12\rangle$$

Find the three cube roots of \(-27 i\)

Solve \(\triangle A B C.\) \(a=286.5, \quad b=286.5, \quad c=10.0\)

Surveying To find the distance between two points \(A\) and \(B\) that lie on opposite banks of a river, a surveyor lays off a line segment \(A C\) of length 240 yards along one bank and determines that the measures of \(\angle B A C\) and \(\angle A C B\) are \(63^{\circ} 20^{\prime}\) and \(54^{\circ} 10^{\prime},\) respectively (see the figure). Approximate the distance between \(A\) and \(B\). (figure cannot copy)

If a \(=\left\langle a_{1}, a_{2}\right\rangle, \mathbf{b}=\left\langle\boldsymbol{b}_{1}, \boldsymbol{b}_{2}\right\rangle, \mathbf{c}=\left\langle\boldsymbol{c}_{1}, \boldsymbol{c}_{2}\right\rangle,\) and \(\boldsymbol{m}\) and \(n\) are real numbers, prove the stated property. $$\mathbf{a}+(\mathbf{b}+\mathbf{c})=(\mathbf{a}+\mathbf{b})+\mathbf{c}$$

Represent the complex number geometrically. $$-2 i(3-2 i)$$