Steps of Construction:

1. Draw a line segment AB of given length 7cm.

2. Draw a line originating from A and making an acute angle with line segment AB.

3. As we have to get 3 parts out of 5 parts of AB. We will divide the line from A into 5 parts.

4. Taking A as center draw an arc cutting at A₁ on the line.

5. With the same radius and taking A1 as a center, draw another arc cutting line at A₂. Repeat the same till A₅, as shown below:

6. Join A₅ and B by drawing a line:

7. Draw lines parallel to A₅B from A_4, A_3, A₃ and A₁ cutting line AB.

8. The Point where the parallel line from A₃ cuts AB is P.

9. Hence P is the required point such that AP/AB = 3/5.