Question

Mark (✓) against the correct answer
A ladder is placed in such a way that its foot is 15 m away from the wall and its top reaches a window 20 m above the ground. The length of the ladder is

(a) 35 m
(b) 25 m
(c) 18 m
(d) 17.5 m

Answer 1

$$\begin{gathered} \left(b\right)25\mathrm{m} \\ \begin{array}{l}\text{In right triangle ABC:}\\ {\text{AC}}^2={\text{AB}}^2+{\text{BC}}^2\\ {\text{=15}}^2+{20}^2\\ {\text{=> AC}}^2=625\\ \text{=>AC}=\pm 25\\ \mathrm{Since}\mathrm{the}\mathrm{length}\mathrm{cannot}\mathrm{be}\mathrm{negative},\mathrm{we}\mathrm{will}\mathrm{negelect}-25.\end{array} \\ \therefore \text{Length of the ladder = 25 m} \end{gathered}$$