panjang qr adalah...

[tex]QS = \sqrt{PS^{2} + {PQ}^{2} - 2PS \times PQ \cos(45) } \\ QS = \sqrt{(8 \sqrt{2})^{2} + {8}^{2} - 2 \times 8 \sqrt{2} \times 8 \times \frac{1}{2} \sqrt{2} } \\ QS = \sqrt{128 + 64 - 128} \\ QS = \sqrt{64} = 8 \\ \frac{QR}{ \sin60} = \frac{QS}{ \sin30} \\ \frac{QR}{ \frac{1}{2} \sqrt{3} } = \frac{8}{ \frac{1}{2} } \\ QR = 8 \sqrt{3} \: cm[/tex]