C. ![\text{area of }\triangle ABC=\dfrac{1}{2}\times BC\times AD](/tpl/images/0174/4128/f7198.png)
Step-by-step explanation:
The common formula is used to find the area of a triangle is
![\dfrac{1}{2}\times\text{base}\times\text{altitude}](/tpl/images/0174/4128/15184.png)
In the given picture , we have a triangle ABC , in which Altitude (making right angle with base) of triangle = AD with corresponding base = BC
Thus , the area of the triangle will be :
![\text{area of }\triangle ABC=\dfrac{1}{2}\times BC\times AD](/tpl/images/0174/4128/f7198.png)
Therefore , the correct options is
C. ![\text{area of }\triangle ABC=\dfrac{1}{2}\times BC\times AD](/tpl/images/0174/4128/f7198.png)