A new pyramid has been found in South America. The pyramid has a rectangular base that measures 75 yd by 180 yd, and has a height of 90 yd. The pyramid is not hollow like the Egyptian pyramids and is composed of layer after layer of cut stone. (a) The stone weighs 456 lb per cubic yard. How many pounds does the pyramid weigh?

A calendar is determined by using each of the 12 faces of a regular dodecahedron for one month of the year. With each side of the regular pentagonal face measuring 4cm, the area of each face is approximately 27.5 cm2. a What is the total surface area of the calendar? b If the material used to construct the calendar costs 0.8 of a cent per square centimeter, what is the cost of the materials used in construction?

Find the area of an equilateral triangle with apothem a = 3.2 cm and perimeter P=19.23 cm.