Question

Resolução com contas desse exercício.

Answer 1

$\frac{SA}{SB} = \frac{DA}{ CB} \\ \frac{SA}{SA + 45} = \frac{30}{180} \\ \frac{SA}{SA + 45} = \frac{1}{6}$

$6SA = SA + 45 \\ 6SA - SA = 45 \\ 5SA = 45 \\ SA = \frac{45}{5} \\SA = 9$

$\frac{SD}{SC} = \frac{SA}{SB} \\ \frac{SD}{SD + 54} = \frac{9}{45} \\ \frac{SD}{SD + 54} = \frac{1}{5}$

$5SD = SD + 54 \\ 5SD - SD = 54 \\ 4SD = 54 \\ SD = \frac{54}{4} = \frac{27}{2}$