The ratio of the altitudes of a triangle is $2:3:4$. If the perimeter is $91 \mathrm{cm}$, then the sides of the triangle are:

If $\mathrm{AC}=\mathrm{CE}=\mathrm{EG}$ and area of $\mathrm{DEFG}=20 {\mathrm{cm}}^2$ , then the area of $\mathrm{BCDE}$ is:

In the figure, $\mathrm{AB} \Vert \mathrm{DC}, \mathrm{DE} \Vert \mathrm{AC}$, then:

In right $∆\mathrm{ABC}, \mathrm{BC}=10 \mathrm{cm}, \mathrm{AB}=24 \mathrm{cm}$ and $\mathrm{AF}=\mathrm{x}, \mathrm{DE}$ and $\mathrm{DF}$ are perpendiculars on side $\mathrm{BC} \& \mathrm{AB}$ from $\mathrm{D}$ (which on $\mathrm{DC}$) If $\mathrm{Y}=\mathrm{DE}+\mathrm{DF}$ (in $\mathrm{cm}$), then: