Question

Triangles ABC and EDC are similar.

ACE and BCD are straight lines.
Angle BAC = angle DEC
Angle CBA= angle CDE
AB = = 6 cm, BC = 2.5 cm, CD = 7.5 cm and CE = 10.5 cm.

Answer 1

Answer is 18. You can use triangle similarity

Answer 2

18cm

Explanation:

The ratio is given by: 7.5/2.5=3

DE = 6 × 3 = 18 cm

or

DC/CB = x/AB

7.5/2.5 = x/6

3=x/6

x=6×3=18 cm