사각형 넓이 방정식

$\displaystyle {\overline{\mathrm{AD}}} = x$라 하면 $\displaystyle {\overline{\mathrm{BC}}} = x + \frac{3}{2}$ $\square {\mathrm{ABCD}}$$= \triangle {\mathrm{ABD}} + \triangle {\mathrm{BCD}}$ $\displaystyle = \frac{1}{2} \times {\overline{\mathrm{AD}}} \times {\overline{\mathrm{CD}}} + \frac{1}{2} \times {\overline{\mathrm{BC}}} \times {\overline{\mathrm{CD}}}$ $\displaystyle = \frac{1}{2} \times x \times 4 + \frac{1}{2} \times \left( x + \frac{3}{2} \right) \times 4$ $= 2 x + \left( 2 x + 3 \right)$ $= 4 x + 3 = 17$ $4 x = 14$, $\displaystyle x = \frac{7}{2}$ 따라서 선분 ${\mathrm{AD}}$의 길이는 $\displaystyle \frac{7}{2}$