Advertisements
Advertisements
Question
In quadrilateral PQRS, ∠P : ∠Q : ∠R : ∠S = 3 : 4 : 6 : 7.
Calculate each angle of the quadrilateral and then prove that PQ and SR are parallel to each other
(i) Is PS also parallel to QR?
(ii) Assign a special name to quadrilateral PQRS.
Advertisements
Solution

∵ ∠P : ∠Q : ∠R : ∠S = 3: 4: 6: 7
Let ∠P = 3x
∠Q = 4x
∠R = 6x
∠S = 7x
∴ ∠P + ∠Q + ∠R + ∠S = 360°
3x + 4x + 6x + 7x = 360°
20x = 360°
x = 18°
∴ ∠P = 3x = 3 × 18 = 54°
∠Q = 4x = 4 × 18 = 72°
∠R = 6x = 6 × 18 = 108°
∠S = 7x = 7 × 18 = 126°
∠Q + ∠R = 72° + 108° = 180°
or ∠P + ∠S = 54° + 126° = 180°
Hence PQ || SR
As ∠P + ∠Q = 72° + 54° = 126°
Which is ≠ 180°
∴ PS and QR are not parallel.
PQRS is a Trapezium as its one pair of opposite side is parallel.
RELATED QUESTIONS
How many diagonals does following have?
A convex quadrilateral
The perimeter of a parallelogram is 22 cm . If the longer side measures 6.5 cm what is the measure of the shorter side?
Complete of the following, so as to make a true statement:
The number of pairs of adjacent angles of a quadrilateral is .......
In Fig. 16.19, ABCD is a quadrilateral.
Name a pair of opposite angles.

The four angles of a quadrilateral are as 3 : 5 : 7 : 9. Find the angles.
In Fig. 16.21, the bisectors of ∠A and ∠B meet at a point P. If ∠C = 100° and ∠D = 50°, find the measure of ∠APB.

Complete the following statement by means of one of those given in brackets against each:
If one pair of opposite sides are equal and parallel, then the figure is ........................
If the bisectors of two adjacent angles A and B of a quadrilateral ABCD intersect at a point O such that ∠C + ∠D = k ∠AOB, then find the value of k.
The consecutive sides of a quadrilateral have
Use the following figure to find the value of x

One diagonal of a rectangle is 18 cm. What is the length of its other diagonal?
One angle of a hexagon is 140° and the remaining angles are in the ratio 4 : 3 : 4 : 5 : 4. Calculate the measures of the smallest and the largest angles.
Which of the following is not true for a parallelogram?
In quadrilateral ROPE, the pairs of adjacent angles are ______.
The number of right angles in a straight angle is ______ and that in a complete angle is ______.
In the following figure, What is AE + EC?

In the following figure, What is BD – DE?

Using the information given, name the right angles in part of figure:
AC ⊥ CD

How many points are required to form a quadrilateral?
In quadrilateral PQRS, which pair represents adjacent sides?
