The sum of the squares on the sides of a rhombus is equal to the sum of the squares on its diagonals.

A man goes $24 \mathrm{m}$ due west and then $10 \mathrm{m}$ due north. How far is he from the starting point?

Two poles of height $13 \mathrm{m}$ and $7 \mathrm{m}$ respectively stand vertically on a plane ground at a distance of $8 \mathrm{m}$ from each other. The distance between their tops is 

A vertical stick $1.8 \mathrm{m}$ long casts a shadow $45 \mathrm{cm}$ long on the ground. At the same time, what is the length of the shadow of a pole of $6 \mathrm{m}$ high?

A vertical pole $6 \mathrm{m}$ casts a shadow of length $3.6 \mathrm{m}$ on the ground. What is the height of a tower which casts a shadow of length $18 \mathrm{m}$ at the same time?

The shadow of a $5-\mathrm{m}$-long stick is $2 \mathrm{m}$ long . At the same time the length of the shadow of a $12.5-\mathrm{m}$-high tree (in $\mathrm{m}$) is

A ladder $25 \mathrm{m}$ long just reaches the top of a building $24 \mathrm{m}$ high from the ground. What is the distance of the foot of the ladder from the building?

In the given figure, $O$ is a point inside a $∆MNP$ such that $\angle MOP=90°, OM=16 \mathrm{cm}$ and $OP=12 \mathrm{cm}$. If $MN=21 \mathrm{cm}$ and $\angle NMP=90°$ then $NP=?$

The hypotenuse of right triangle is $25 \mathrm{cm}$. The other two sides are such that one is $5 \mathrm{cm}$ longer than the other. The lengths of these sides are