Chapter 5: Understanding Quadrilaterals & Practical Geometry

Solution:-

(b) 3

To construct a unique parallelogram, we need the measurement of two adjacent sides of the parallelogram and the angle between them.

Solution:-

(c) 2

To construct a unique rectangle, we need only the measurement of the length and the breadth of a rectangle.

In questions 53 to 91, fill in the blanks to make the statements true.

Solution:-

In quadrilateral HOPE, the pairs of opposite sides are HO and PE, HE and OP.

Solution:-

In quadrilateral ROPE, the pairs of adjacent angles are RO and OP, OP and PE, PE and ER, ER and RO.

Solution:-

In quadrilateral WXYZ, the pairs of opposite angles are ∠W and ∠Y, ∠X and ∠Z.

Solution:-

The diagonals of the quadrilateral DEFG are DF and EG.

Solution:-

The sum of all angles of a quadrilateral is 360^o.

Solution:-

The measure of each exterior angle of a regular pentagon is 72^o.

We know that, the measure of each exterior angle of a regular pentagon is 360^o/n.

Where ‘n’ is the number of sides in the polygon,

Then, pentagon has 5 sides, i.e. n = 5

So, 360^o/5

= 72^o

Solution:-

Sum of the angles of a hexagon is 720^o.

We know that, the sum of all the angles of a polygon is (n – 2) × 180^o.

Where ‘n’ is the number of sides in the polygon,

Then, hexagon has 6 sides, i.e. n = 6

So, (n – 2) × 180^o

(6 – 2) × 180^o

4 × 180^o

720^o

Solution:-

The measure of each exterior angle of a regular polygon of 18 sides is 20^o.

We know that, the measure of each exterior angle of a regular polygon is 360^o/n.

Where ‘n’ is the number of sides in the polygon,

Then, polygon has 18 sides, i.e. n = 18

So, 360^o/18

= 20^o