Question

In the given figure if AB = 17 cm, DC =11 cm and BC = 8 cm, then AD = ___ cm.

• A. 9
• B. 8
• C. 15
• D. 10

Answer 1

The correct option is D

10

Draw $DE\perp AB$

BEDC is a rectangle

$BE=DC=11cm$

$AE=17–11=6cm$

$ED=BC=8cm$

In $\Delta AED$

Using Pythagoras Theorem we have,

$A{D}^2=A{E}^2+E{D}^2$

$A{D}^2=6^2+8^2$

$A{D}^2=36+64$

$A{D}^2=100$

$AD=10cm$