The measure of each interior angle of a regular nonagon is:

 

An equiangular parallelogram is known as:

In which of the quadrilateral, only one pair of opposite sides are parallel?

In which of the quadrilaterals, only one pair of opposite angles are equal?

Seema used the formula $\frac{n\left(n-1\right)}{2}-n$ for finding the number of diagonals of a polygon instead of $\frac{n\left(n-3\right)}{2}$. Is Seema right or wrong?

Can the following figure be a parallelogram? Justify your answer

Can the following figure be a parallelogram? Justify your answer

Can the following figure be a parallelogram? Justify your answer

Two regular polygons are such that the ratio of the number of their sides is $1 : 2$ and the ratio measure of their interior angles is $3 : 4$. Find the number of sides of each polygon.