57) How many links are available in a 30 M metric chain?

58) What is the required length of a diagonal scale with RF = 1/20 and length to be measured is 2 m?

59) Which solid has eight equilateral triangular faces?

60) Which lines are used to indicate arcs of symmertical objects featrures?

61) Calculate the actual size of component in metres(m), if the size of a component in the drawing is 15 mm and RF = 0.0075.