Mathematics

Problem

Which of the following correctly represents the area

A

of a convex quadrilateral

ABCD

in terms of the areas of the two triangles formed by its diagonal

AC

? a)

A = \dfrac{A_{\triangle ABC} + A_{\triangle ADC}}{2}

A = A_{\triangle ABC} + A_{\triangle ADC}

A = A_{\triangle ABC} \times A_{\triangle ADC}

A = \sqrt{A_{\triangle ABC}^2 + A_{\triangle ADC}^2}