CBSE Class 8 Maths Understanding Quadrilaterals Question Bank

Question. The angle of a quadrilateral are respectively \( 100^\circ, 98^\circ, 92^\circ \). Find the fourth angle.
Answer: \( 70^\circ \)

Question. Three angles of a quadrilateral are respectively equal to \( 110^\circ, 50^\circ \) and \( 40^\circ \). Find its fourth angles.
Answer: \( 160^\circ \)

Question. In a quadrilateral ABCD, the angles A, B, C and D are in the ratio \( 1 : 2 : 4 : 5 \). Find the measure of each angles of the quadrilateral.
Answer: \( 30^\circ, 60^\circ, 120^\circ, 150^\circ \)

Question. In \( \Delta ABC \), P Q and R are mid-points of sides BC, CA and AB respectively. If \( AC = 21 \) cm, \( BC = 29 \) cm and \( AB = 30 \) cm, find the perimeter of the quadrilateral ARPQ.
Answer: \( 51 \text{ cm} \)

Fill in the Blanks

Question. The triangle formed by joining the mid-points of the sides of an isosceles triangle is.........
Answer: Isosceles

Question. The triangle formed by joining the mid-points of the sides of a right triangle is .......... .
Answer: Right triangle

Question. The figure formed by joining the mid-points of consecutive sides of a quadrilateral is.........
Answer: Parallelogram

True/False Type Questions

Question. In any quadrilateral, if a pair of opposite sides is equal, it is a parallelogram.
Answer: False

Question. If all the angles of a quadrilateral are equal, it is a parallelogram.
Answer: True

Question. If three sides of a quadrilateral are equal, it is a parallelogram.
Answer: False

Question. If three angles of a quadrilateral are equal, it is a parallelogram.
Answer: False

Question. If all the sides of a quadrilateral are equal it is a parallelogram.
Answer: True

Question. In a parallelogram ABCD, \( AB = 10 \) cm and \( AD = 6 \) cm. The bisector of \( \angle A \) meets DC in E. AE and BC produced meet at F. Find the length of CF.
Answer: \( 4 \text{ cm.} \)-//-

Question. In which quadrilateral is the lengths of diagonals equal ?
Answer: Rectangle

Question. If the diagonals of a quadrilateral bisect each other at right angles, then it is a :
Answer: Rhombus

Question. The length of the diagonals of a rhombus are \( 16 \) cm and \( 12 \) cm. The side of the rhombus is -
Answer: \( 10 \text{ cm} \)

Question. The length of a side of a rhombus is \( 5 \) m and one of its diagonals is of length \( 8 \) m. Find the length of the other diagonal
Answer: \( 6 \text{ m} \)

Question. Find the angle where the bisectors of any two adjacent angles of a parallelogram intersect
Answer: \( 90^\circ \)

Question. Give name of the figure formed by joining the mid points of the adjacent sides of a quadrilateral :
Answer: Parallelogram

Question. Name the figure formed by joining the mid points of the adjacent sides of a rectangle
Answer: rhombus

Question. Three angles of a quadrilateral are of magnitudes \( 80^\circ, 95^\circ \) and \( 120^\circ \). Find the magnitude of the fourth angle
Answer: \( 65^\circ \)

Question. Two consecutive angles of a parallelogram are in the ratio \( 1 : 3 \). Find the smaller angle
Answer: \( 45^\circ \)

Question. If three angles of a quadrilateral are \( 100^\circ, 75^\circ \) and \( 105^\circ \), then find the measure of the fourth angle
Answer: \( 80^\circ \)

Question. The diagonals of a rhombus are \( 12 \) cm and \( 16 \) cm. Find the length of the side of the rhombus
Answer: \( 10 \text{ cm} \)