In $△FAN, \angle F= 80°,\angle A=40°$. Find out the greatest and the smallest side of the triangle. State the reason.

Prove that, if the bisector of $\angle BAC$ of $∆ABC$ is perpendicular to side $BC$, then $∆ABC$ is an isosceles triangle.

In figure, if $\mathrm{segment} \mathrm{PR}=\mathrm{segment} \mathrm{PQ}$, show that $\mathrm{segmenet} \mathrm{PS}>\mathrm{segment} \mathrm{PQ}$.

In $\Delta ABC$, segment $AD$ and segment $BE$ are altitudes and $AE=BD$. Prove that segment $AD\cong$ segment $BE$.

If$\Delta XYZ ~ \Delta LMN$write the corresponding angles of the two triangles and also write the ratios of corresponding sides.

In $\Delta XYZ$, $XY=$$4 \mathrm{cm}$, $YZ=$$6 \mathrm{cm}$, $XZ=$$5 \mathrm{cm}$, if $\Delta XYZ ~ \Delta PQR$ and $PQ=8 \mathrm{cm}$, then find the lengths of remaining sides of $\Delta PQR.$

Draw a sketch of a pair of similar triangles. Label them. Show their corresponding angles by the same signs. Show the lengths of corresponding sides by numbers in proportion.

If two sides of a triangle are $5 \mathrm{cm}$ and $1.5 \mathrm{cm}$, the length of its third side cannot be