well, Matti's house is a triangular prism, and to get the volume of it, we simply get the area of the triangle upfront and multiply by its length of 15.

Density = m/v with mass being in grams and volume in mL......
192 grams/250 mL = 0.768 g/mL
Since both C & D are parallel, angle 2 is a corresponding angle to the angle of 108 degrees, so angle 2 is also 108 degrees
2/9=0.222
The answer would be 0.