in attachments
think 17 is A. 25.6 not sure
17)
$\displaystyle
\overline{NL} = 2\times\overline{JL} = 2\times 12.8 = 25.6
$
OR
$\displaystyle
\overline{NL} = \overline{MK}
$
$\displaystyle
\overline{MK} = \sqrt{\overline{NM}^2 + \overline{NK}^2} = \sqrt{16^2 +20^2} = \sqrt 656 \doteq 25.6
$
23) and 27)
$\displaystyle
\overline {RT} = \overline {TP} = \overline {PS}
$
$\displaystyle
\sqrt{(\overline {RT}+ \overline {TP})^2 - \overline {PS}^2} = \overline {SR}
$
$\displaystyle
\sqrt{(2\times\overline{RT})^2 - \overline{PS}^2} = \overline{SR}
$
$\displaystyle
\sqrt{(2\times5)^2 - 5^2} = \overline {SR}
$
$\displaystyle
\overline {SR} = \sqrt {75} = 5\sqrt{3} \doteq 8.7
$
29)
$\displaystyle
\overline{AC} = 3x
$
$\displaystyle
\overline{BD} = 7x - 8
$
$\displaystyle
\overline{AC} = \overline {BD}
$
$\displaystyle
3x = 7x - 8
$
$\displaystyle
4x = 8
$
$\displaystyle
x = 2
$
$\displaystyle
\overline{AC} = \overline {BD} = 3x = 3\times2 = 6
$