The straight lines setting forth the flat and curved surfaces should be drawn in. A 1-inch lap is added to the curved surfaces.
71. Related Mathematics on Rotary Ash Sifter.—
Areas of Trapezoids.
Problem 37A.—What is the area of Fig. 216? Of Fig. 217? Of Fig. 218? Of Fig. 219? Of Fig. 225?
Area of Circle.
Problem 37B.—Find the area of Fig. 220, using the over-all dimensions. What per cent of the metal is cut away for the opening?
Area of Rectangle.
Problem 37C.—Compute the area of Fig. 221 by using the overall dimensions.
Areas of Triangles.
Problem 37D.—Divide the pattern of the sides of Fig. 225 into triangles and compute the area of each.
Problem 37E.—What is the combined total area of both sides?
Problem 37F.—Treating Fig. 229 as a combination of triangles, what is its area?
Frustums of Cones.
Problem 37G.—What is the area in square inches of Fig. 223?
Problem 37H.—By drawing the imaginary line between points 5 and 13, Fig. 228 would be converted into a trapezoid. What would be its area?
Problem 37–I.—What is the combined area of all of the patterns required for the rotary ash sifter?
