Question

In ∆ ABC,D is a point on side BC such that B-C-D if BD =12 cm ,CD=4cm then what is the value of A(∆ACD): A(∆ABC)?

Answer 1

Answer:

1:2

Step-by-step explanation:

As you can see in the diagram, D lies on BC extended.

BD=12cm, CD=4cm

∴BC=12-4=8cm

Let AE=h (where h is height/altitude of the triangle)

ar(ΔABC)=1/2 (BC).(AE)=1/2 (8).(h)

Similarly

ar(ΔACD)=1/2 (CD).(AE)=1/2 (4).(h)   (ACD is an obtuse angled triangle the altitude is measures externally)

Hence required ratio is $\frac{\frac{1}{2} h.4}{\frac{1}{2} h.8}$

=1:2