Quadrilaterals and Polygons
Three vertices of a parallelogram $$ABCD$$ are $$A (3, -1, 2), B(1, 2, -4)$$ and $$C (-1, 1, 2)$$. Find the coordinates of the fourth vertex.
The sum of two opposite angles of a parallelogram is $$130^o$$. Find the measure of each of its angles.
$$ABCD$$ is a parallelogram.
$$\angle B+\angle D=130^{\circ}$$
$$\angle B=\angle D$$ (opposite angles of a parallelogram are equal)
$$\angle B=\angle B=130^{\circ}$$
$$2\angle B=130^{\circ}$$
$$\angle B=\dfrac{130^{\circ}}{2}$$
$$\angle B=65^{\circ}$$
Now $$\angle B+\angle C=180^{\circ}$$ (adjacent angles of a parallelogram are supplementary )
$$\angle C=180^{\circ}-\angle B=180^{\circ}-65^{\circ}$$
$$\angle C=115^{\circ}$$
$$\therefore \angle A=\angle C=115^{\circ}$$ (opp. angles of parallelogram are equal)
$$\therefore \angle B=\angle D=65^{\circ}$$ and $$\angle A=\angle C=115^{\circ}$$
Three vertices of a parallelogram $$ABCD$$ are $$A (3, -1, 2), B(1, 2, -4)$$ and $$C (-1, 1, 2)$$. Find the coordinates of the fourth vertex.
The measures of two adjacent angles of a parallelogram are in the ratio $$3 : 2$$. Find the measure of each of the angles of the parallelogram.
The measure of two adjacent angles of a parallelogram are in the ratio 4 : 5. Find the measure of each angle of the parallelogram.
The perimeter of a parallelogram is 140 cm. If one of the sides is longer than the other by 10 cm,find the length of each of its sides.
$$ABCD$$ is a parallelogram in which $$\angle {110^{o}}.$$ Find the measure of each of angles $$\angle B,\ \angle C$$ and $$\angle D.$$
Two adjacent angles of a parallelogram are $$\left(2x+25\right)^{o}$$ and $$\left(3x-5\right)^{o}.$$ The value of $$x$$ is
The diagonals do not necessarily intersect at right angles in a
Two adjacent side of a parallelogram are 15 cm. If the distance between the longer sides is 8 cm , find the ares of the parallelogram. Also find the distance between shorter sides.
Show that the diagonals of a parallelogram divide it into four triangles of equal area.
(a) In the figure ( 1 ) given below, the perimeter of parallelogram is $$ 42 \mathrm{cm} $$. Calculate the lengths of the sides of the parallelogram.