Construct a regular octagon inscribed in a circle of a radius of $3 \mathrm{cm}$.

Construct a quadrilateral $\mathrm{ABCD}$, where $\mathrm{AB}=5 \mathrm{cm}, \mathrm{BC}=6 \mathrm{cm}, \mathrm{CD}=7 \mathrm{cm}$ and $\angle \mathrm{B}=\angle \mathrm{C}=90°.$ Then on $\mathrm{AB}$ as base construct a triangle which is equal in area to that of the quadrilateral.

Construct a triangle whose area is equal to the area of the rhombus whose sides are of $6 \mathrm{cm}$ and one angle of $60°$.

Construct an isosceles triangle with a base of $6 \mathrm{cm}$ and base angles of $70°$, construct a parallelogram and rectangle which is equal in area to that of the triangle.

Construct a triangle $\mathrm{PQR}$ where $\mathrm{PQ}=8 \mathrm{cm}, \mathrm{PR}=6 \mathrm{cm}, \angle \mathrm{QPR}=65°$. Construct a parallelogram whose area is equal to the area of the triangle.