Question

In the given figure, $AD=BC.$ What is the length of $AB$ if $DC=4cm?$

• A. 5 cm
• B. 4 cm
• C. 3 cm
• D. Can’t find

Answer 1

The correct option is B

4 cm

In $\Delta ABC$ and $\Delta ADC,$ we have
$AD=BC$ [given]
$AC=AC$ [common side]
and, $\angle ADC=\angle ABC={90}^{\circ }$
Thus, $\Delta ABC\cong \Delta ADC$
Therefore, $AB=DC=4cm$ [CPCTE]