Question

In $\Delta ABC$, AC $>$ AB and AD bisects $\angle A$. Which of the following option is correct?

• A. ADC ADB
• B. ADC ADB
• C. ADC = ADB
• D. None of these

Answer 1

The correct option is A

ADC ADB

In $\Delta ABC$, it is given that AC $>$ AB, which means $\angle B$ $>$ $\angle C$.

Now, AD bisects $\angle A$,
So, in $\Delta ADC$, $\angle ADC$ = ${180}^{\circ }$ - $(\frac{\angle A}{2}$ + $\angle C)$
Similarly, in $\Delta ADB$, $\angle ADB$ = ${180}^{\circ }$ – $(\frac{\angle A}{2}$ + $\angle B)$

and since $\angle B$ in $\Delta ADB$ is greater than $\angle C$ in $\Delta ADC$, and $\frac{\angle A}{2}$ is common (AD is the bisector),
we can deduce that $\angle ADB$ is smaller than $\angle ADC$.