We will use the concept of similar triangles to solve this problem. We will use two triangles: ΔABC and ΔCBD. Next we will establish relations between them. Given that:
BC = m
AC = 18
AD = 11
DC = 7
We will name the some angles as follows:
∠ACB = ∠DCB = β
So the following relations from the triangles are equal to:
(1)
(2)
So, matching these equations:
Solving for m:
∴
BC = m
AC = 18
AD = 11
DC = 7
We will name the some angles as follows:
∠ACB = ∠DCB = β
So the following relations from the triangles are equal to:
(1)
(2)
So, matching these equations:
Solving for m:
∴