Question

It is given that $\Delta ABC\cong \Delta FDE$ and $AB$ = $5cm$, $\angle B={40}^0$ and $\angle A={80}^0.$ Then which of the following is true?

• A. $DF=5cm,\angle F={60}^0$
• B. $DF=5cm,\angle E={60}^0$
• C. $DE=5cm,\angle E={60}^0$
• D. $DE=5cm,\angle D={40}^0$

Answer 1

The correct option is B $DF=5cm,\angle E={60}^0$

Two triangles are congruent if their corresponding sides are equal in length and their corresponding angles are equal in size.

In the first option, $DF=5$ cm but $\angle F$ is not equal to ${60}^{\circ }$.

In the third and the fourth options, the length of $DE\ne 5$cm, since it is not defined.

In the second option, $DF=5$cm and $\angle E={60}^{\circ }$ is satisfied.