STEP 1: find side $ a $
To find side $ a $ use formula:
$$ r = \dfrac{ a }{ 2 } $$After substituting $ r = 5.7 $ we have:
$$ 5.7 = \dfrac{ a }{ 2 } $$ $$ a = 5.7 \cdot 2 $$ $$ a = 11.4 $$STEP 2: find slant height $ s $
To find slant height $ s $ use Pythagorean Theorem:
$$ h^2 + \frac{ a^2 }{ 4 } = s^2 $$After substituting $ h = 8.6 $ and $ a = 11.4 $ we have:
$$ 8.6^2 + \frac{ 11.4^2 }{ 4 }= s^2 $$ $$ 73.96 + \frac{ 129.96 }{ 4 }= s^2 $$ $$ 73.96 + 32.49 = s^2 $$ $$ s^2 = 106.45 $$ $$ s = \sqrt{ 106.45 } $$$$ s = 10.3175 $$