In the given figure, the value of AB × CD is :

1. AC × BC

2. AC × CD

3. AC × AB

4. AC² + BC²

By formula,

⇒ Area of triangle = $\dfrac{1}{2}$ × base × height

From figure,

⇒ Area of △ ABC = $\dfrac{1}{2}$ × AB × CD ………(1)

⇒ Area of △ ABC = $\dfrac{1}{2}$ × BC × AC ………(2)

From equations (1) and (2), we get :

⇒ $\dfrac{1}{2}$ × AB × CD = $\dfrac{1}{2}$ × BC × AC

⇒ AB × CD = BC × AC.

Hence, Option 1 is the correct option.