Question

From the similar triangles in the diagram, write a proportion using the ratio BC/DC.

1) BC/DC=AB/AD
2) BC/DC=AD/AB
3) BC/DC= AB/DB
4) BC/DC=AD/BD

Answer 1

there are 3 triangles, they are similar
* the triangle ABD similar with ABC,
AB/AC = AD/AB or
AB^2 = AC * AD

** the triangle BCD similar with ABC,
BC/AC = CD/BC or
BC^2 = AC * CD

***the triangle ABD similar with BCD,
BD/CD = AD/BD or
BD^2 = CD * AD