# math

posted by
**Kheladi Nep**
.

Triangle ABD in the diagram has a right angle A and sides AD = 4.9cm and AB = 7.0cm. side AB is extended to C so that ABC is a straight line.

a) use pythagoras theorem in triangle ABD to find the length of BD.

b)use trigonometry in triangle ABD to find angle ABD. hence find angle DBC.

c)angle BCD=21* use the sine formula in triangle BCD to find the length of CD

d)use the cosine formula in triangle BCD to find the length of BC