Herons Formula ...

If $$\triangle ABC$$ is a right isosceles triangle with hypotenuse $$AC= 10$$ $$cm$$ and right angle at $$B$$, then the twice of its area is ____.

Riya has a piece of cloth in the shape of equilateral triangle whose all altitudes are equal to $$6$$ $$cm$$. Find its area. (if each of it's sides are  $$4 \sqrt 3$$ cm)

In the given figure, it is given that $$O$$ is a mid point of $$AB$$ and $$CD$$, $$ AB = 24$$ units and $$CD = 26$$ units. Find the value of $$ar( \triangle OBC) + 2 ar( \triangle OAD).$$

Find $$ar(\triangle ABD).$$

Ankita has a piece of cake in the shape of an equilateral triangle whose all altitudes are equal to $$8$$ $$cm$$. Then the half of its area is ____. (if each side is equal to $$\dfrac {27 \sqrt 3}{2}$$)

Find area of triangle ADC.

Diya has a lunch box in the shape of right isosceles triangle of hypotenuse $$30$$ $$cm$$, find its area.

Find the area of triangle ABD.

In given figure, $$AC= 5$$ $$cm$$, $$BD = 2 $$ $$cm$$ and $$CD = 2BD$$. Find the area of $$\triangle ABC$$.

How much paper of blue shade is needed to make a kite given in the figure, if $$AB = BC = 10$$ $$cm$$ and $$BO = 8 $$ $$cm$$?