Tolong dijawab dengan caranya makasih

18. perbandingan panjang sisi segitiga:
[tex]1 \div 1 \div \sqrt{2} \\ maka \: ab = 12 \sqrt{2} [/tex]
19.[tex] \tan(30) = \frac{3}{ps} \\ \frac{1}{ \sqrt{3} } = \frac{3}{ps} \\ ps = 3 \sqrt{3} [/tex]
[tex] \tan(60) = \frac{3}{sr} \\ \sqrt{3} = \frac{3}{sr} \\ sr = \sqrt{3} \\ panjang \: pr = 3 \sqrt{3} + \sqrt{3} = 4 \sqrt{3} [/tex]
20.
[tex] \sin(60) = \frac{t}{12} \\ \frac{ \sqrt{3} }{2} = \frac{t}{12} \\ t = 6 \sqrt{3} \\ luas = 15 \times 6 \sqrt{3} = 90 \sqrt{3} [/tex]