Question

Length of a curved line can be measured by using a –
A. Ruler
B. String
C. Cubit
D. Hand-span

Answer 1

Hint: A curved line is a bent line which is not straight. It does not move in a particular direction. In order to measure a curved line, we need a substance which can trace both the shape and direction of the curved line. It should not be stiff and should be flexible enough to bend with curves.

Complete step-by-step answer:
In order to measure a curved line, a string is used. A knot is created at one end of the string which is regarded as the starting point and placed at the beginning of the line. Try to measure a small potion of line which is relatively straight. Place your thumb at the other end of the measured portion and measure the next straight portion and repeat to trace the rest of the curved path. After this stretch the string and measure it against a meter scale.
So, the correct answer is “Option B”.

Note: According to the options given,
A. Ruler – This cannot be used to measure a curved line because a ruler is very stiff and will not bend with the curved line while measuring it.
B. String is the correct option.
C. Cubit- This is a unit of linear measurement in ancient times. Since it is used for linear measurement, it cannot be used here.
D. Hand-span is the maximum distance between the tips of the thumb and little finger taken as the basis of measurement equal to 9 inches. Hand-span cannot be used to measure a curved line because it is not a universally accepted scale since the size of the fingers varies from person to person.