In a triangle $ABC$, with usual notation, if $a=12, b=16, c=20$, then the ratio of the exradii of the triangle opposite to the angles in the order $\angle C, \angle B, \angle A$ is

If $a, b, c$ are the sides of a $\Delta ABC$ and exradii $r_1, r_2, r_3$ are respectively $12, 6, 4$, then $a+2b+3c=$

In $\Delta ABC,$ the lengths of sides $AC$ and $AB$ are $12 \, cm$ and $5 \, cm,$ respectively. If the area of $\Delta ABC$ is $30 \, cm^{2}$ and $R$ and $r$ are respectively the radii of the circumcircle and incircle of $\Delta ABC,$ then the value of $2R + r$ (in $cm$) is equal to ....... .

In $\triangle ABC$,if $a: b: c = 4: 5: 6$,then the ratio between the circumradius and the inradius is

The difference between the areas of the circumcircle and the incircle of a regular decagon of side $2 \, cm$ is -

The area of the equilateral triangle which contains three coins of unit radius is