Question

Given AB of length 3.9 cm, construct PQ such that the length of PQ is twice
that of AB. Verify by measurement.
P​

Answer 1

Constructing a line PQ such that its length is twice of line segment AB.

• Draw a line segment AB = 3.9 cm.
• Draw a line $l$.
• Mark a point P on this line.
• Measure 3.9 cm from compass and draw an arc on line. Mark this point as C.
• From C and with same radius, draw another arc on line $l$. Mark this point as Q.
• This is the required line PQ.

Verification:

• PQ = QC + CP

              = 3.9 + 3.9

              = AB + AB

              = 2AB

• Therefore, PQ is the line with a length twice that of AB.

Answer 2

Answer:

7.8 cm will be the answer of twice 3.9