## Solved Problem 13 | Rectangular Parallelepiped

Problem 13
The figure represents a rectangular parallelepiped; AD = 20 in., AB = 10 in., AE = 15 in.
(a) Find the number of degrees in the angles AFB, BFO, AFO, BOF, AOF, OFC.
(b) Find the area of each of the triangles ABO, BOF, AOF.
(c) Find the perpendicular distance from B to the plane AOF. ## Solved Problem 12 | Rectangular Parallelepiped

Problem 12
In the figure is shown a rectangular parallelepiped whose dimensions are 2, 4, 6. Points A, B, C, E, F, and L are each at the midpoint of an edge. Find the area of each of the sections ABEF, ABC, and MNL. ## Solved Problem 09 | Rectangular Parallelepiped

Problem 9
A solid concrete porch consists of 3 steps and a landing. The steps have a tread of 11 in., a rise of 7 in., and a length of 7 ft.; the landing is 6 ft. by 7 ft. How much material was used in its construction? ## Solved Problem 08 | Rectangular Parallelepiped

Problem 8
An electric refrigerator is built in a form of rectangular parallelepiped. The inside dimensions are 3 ft. by 2.6 ft. by 1.8 ft. A freezing unit (1.1 ft. by 0.8 ft. by 0.7 ft.) subtracts from the storage room of the box. Find the capacity of the refrigerator.

## Solved Problem 06 | Rectangular Parallelepiped

Problem 6
A tank, open at the top, is made of sheet iron 1 in. thick. The internal dimensions of the tank are 4 ft. 8 in. long; 3 ft. 6 in. wide; 4 ft. 4 in. deep. Find the weight of the tank when empty and find the weight when full of salt water. (Salt water weighs 64 lb/ft3 and iron is 7.2 times as heavy as salt water.

## Solved Problem 05 | Rectangular Parallelepiped

Problem 5
How many cubic yard of material are needed for the foundation of barn 40 by 80 ft., if the foundation is 2 ft thick and 12 ft. high. 