D) False — area is $ \frac12ab $, and $ r s = r \cdot \fraca+b+c2 $, and $ r = \fraca+b-c2 $, so $ r s = \fraca+b-c2 \cdot \fraca+b+c2 = \frac(a+b)^2 - c^24 = \fraca^2 + 2ab + b^2 - c^24 $. Since $ c^2 = a^2 + b^2 $, this becomes $ \frac2ab4 = \fracab2 $ — yes. - Portal da Acústica