Question

Given $\overline{AB}$ of length 3.9 cm, construct $\overline{PQ}$ such that the length $\overline{PQ}$ is twice that of AB . Verify by measurement.
(Hint: Construct $\overline{PX}$ such that length of $\overline{PX}$ = length of $\overline{AB}$;
then cut off $\overline{XQ}$ such that $\overline{XQ}$ also has the length of $\overline{AB}$.)

Answer 1

Steps of construction:

(i) Draw a line '$l$'.
(ii) Construct $\overline{PX}$ such that length of $\overline{PX}$ = length of $\overline{AB}$
(iii) Then cut of $\overline{XQ}$ such that $\overline{XQ}$ also has the length of $\overline{AB}$.
(iv) Thus the length of $\overline{PX}$ and the length of $\overline{XQ}$ added together make twice the length of $\overline{AB}$

Verification:

By measurement, we find that PQ = 7.8

= 3.9 cm + 3.9 cm

= $\overline{AB}$ + $\overline{AB}$
= 2 × $\overline{AB}$