Area of a parallelogram $=$ .........

For an equilateral triangle,each of whose side is $a$,the length of any altitude of that triangle is ...........

$A$ field is shaped like an equilateral triangle. Its length is $120 \, m$ on each side. Calculate its area using Heron's formula.

The lengths of the sides of a triangle are $13 \, cm$,$13 \, cm$,and $10 \, cm$. Find its area. Also,find the length of the altitude from the opposite vertex to the side whose length is $10 \, cm$.

The sides of a triangle are $56 \ cm$,$60 \ cm$,and $52 \ cm$ long. Then the area of the triangle is (in $cm^2$)

$A$ design is made on a rectangular tile of dimensions $50\, cm \times 70\, cm$ as shown in the figure. The design shows $8$ triangles,each with sides $26\, cm, 17\, cm$,and $25\, cm$. Find the total area of the design and the remaining area of the tile.