Comparative Scale
Comparative scales: These are the scales having the same R.F. but graduated to read different units. These scales may be plain scales or Diagonal scales and may be constructed separately or one above the other. Problems on comparative scales 1 ] A distance of 40 miles is represented by a line 8 cm long. Construct a plain scale to read kilometers up to 120 km(1 m=1.609 km) SOLUTION STEPS : Scale of miles: 40 miles are represented = 8 cm 80 miles = 16 cm R.F = 8/40 x 1609 x 1000 x 100 = 1/8,04,500 Construction: Take a line 16 cm long and divide it into 8 parts. Each will represent 10 miles. Subdivide the first part and each sub-division will measure a single mile. Scale of km: Length of scale = 1/8,04,500 x 120 x 1000 x 100 = 14.90 cm Construction : On the top line of the scale of miles cut off a distance of 14.90 cm and divide it into 12 equ...