
RS Aggarwal Solutions for Class 8 Maths Chapter 16 Exercise 16.1: The Physics Wallah academic team has provided a comprehensive answer for Chapter 16 Parallelograms in the RS Aggarwal class 8 textbook. Before examining the Chapter sixteen parallelogram solution, before attempting to solve all of the numerical problems in Exercise-16A, it is necessary to have a thorough understanding of Chapter 16 Parallelograms.
To do this, read the theory of Chapter 16 Parallelograms. Use NCERT solutions to help you tackle class 8 questions and get good grades. For Maths class 8, Physics Walla expert posted NCERT solutions.RS Aggarwal Solutions for Class 8 Maths Chapter 16 Exercise 16.1 PDF
(1) ABCD is parallelogram in which ∠A = 110 o . Find the measure of each of the angles ∠B, ∠C and ∠D.
Solution: It is a given that ABCD is a parallelogram in which ∠A = 110 o . Since, the sum of any two adjacent angles of a parallelogram is 180 o , we have ∠A + ∠B = 180 o ⇒ ∠B = 180 o – 110 o ⇒ ∠B = 70 o Also, ∠B + ∠C = 180 o ⇒ ∠C = 180 o – 70 o ⇒ ∠C = 110 o Further, ∠C + ∠D = 180 o ⇒ ∠D = 180 o – 110 o ⇒ ∠D = 70 o∴ ∠B = 70 o , ∠C = 110 o and ∠D = 70 o .
(2) Two adjacent angles of a parallelogram are equal. What is the measure of each of these angles?
Solution: Let the measure of each equal angle be x o . ∴ x + x = 180 o ⇒ 2x = 180 ⇒ x = 90 Hence, the measure of each angle is 90 o .(3) Two adjacent angles of a parallelogram are in the ratio 4 : 5. Find the measure of each of its angles.
Solution: Let the measure of the adjacent angles be 4x and 5x ∴ 4x + 5x = 180 ⇒ 9x = 180 ⇒ x = 20 Therefore the measure of the required angle is ∠A = 4 × 20 = 80 o ∠B = 5 × 20 = 100 o ∠B + ∠C = 180 o ⇒ ∠C = 180 o – 100 o = 80 o ∠C + ∠D = 180 o ⇒ ∠D = 180 o – 80 o = 100 o(4) Two adjacent angles of a parallelogram are (3x – 4) o and (3x + 16) o . Find the value of x and hence find the measure of each angles.
Solution: (3x – 4) + (3x + 16) = 180 ⇒ 3x – 4 + 3x + 16 = 180 ⇒ 6x + 12 = 180 ⇒ 6x = 180 – 12 ⇒ 6x = 168 ⇒ x = 28 Therefore, the measure of the each angle is ∠A = (3× 28 – 4) = 80 o ∠B = (3× 28 + 16) = 100 o(5) The sum of two opposite angles of a parallelogram is 130 o . Find the measure of each of its angles.
Solution: ∠A + ∠C = 130 Let the measure of ∠A = ∠C = x ∴ 2x = 130 ⇒ x = 65 Therefore, ∠A = 65 ∴ ∠A + ∠B = 180 ⇒ ∠B = 180 – 65 ⇒ ∠B = 115 ∠C = 65 ∴ ∠C + ∠D = 180 ⇒ ∠D = 180 – 65 ⇒ ∠D = 115.(6) Two sides of a parallelogram are in the ratio 5 : 3. If its perimeter is 64 cm, find the lengths of its sides.
Solution: Let the measure of the sides be 5x and 3x. Its perimeter = 2(5x + 3x) ∴ 2(5x + 3x) = 64 ⇒ 16x = 64 ⇒ x = 4 Therefore, one side = 5 × 4 = 20 Other side = 3 × 4 = 12(7) The perimeter of a parallelogram is 140 cm. If one of the sides is longer than the other by 10cm, find the length of each of its sides.
Solution: Let the length of one side be x cm and other is (x + 10) cm. ∴ 2(x + x + 10) = 140 ⇒ 4x + 20 = 140 ⇒ 4x = 140 – 20 ⇒ 4x = 120 ⇒ x = 30 Length of one side is 30 cm and other side = (30 + 10) = 40 cm.(8) In the adjacent figure, ABCD is a rectangle. If BM and DN are perpendiculars from B and D on AC, prove that ∆BMC ≅ ∆DNA. Is it true that BM = DN?
Solution: In ∆BMC and ∆DNA:
∠DNA = ∠BMC = 90
o
∠BCM = ∠DAN (alternative angles)
BC = DA (opposite sides)
By AAs congruency criteria:
∆BMC ≅ ∆DNA (proved)
So, we can write BM = DN.
(9) In the adjacent figure, ABCD is a parallelogram and line segments AE and CF bisect the angles A and C respectively. Show that AE ∥ CF.
Solution: In ∆ADE and ∆CBF,
We have AD = BC, ∠B = ∠D and ∠DAE = ∠BCF
∵ ∠A = ∠C
And therefore, CD – DE = AB – BF
So, CE = AF
∴ AECF is a parallelogram.
Hence, AE ∥ CF.
(10) The lengths of the diagonals of a rhombus are 16 cm and 12 cm respectively. Find the length of each of its sides.
Solution: We know that the diagonals of a rhombus bisect each other at right angles. Ac and BD are intersecting at a point O.
Therefore, length of each side is 10 cm. Because all sides of a rhombus are equal.
(11) In the given figure ABCD is square. Find the measure of ∠ CAD.
Solution: In ∆ADC,
DA = DC
⇒ ∠ACD = ∠DAC = x
o
Then, x
o
+ x
o
+ 90
o
= 180
o
⇒ 2x
o
= 180
o
– 90
o
⇒ 2x
o
= 90
o
⇒ x
o
= 45
o
(12) The sides of a rectangle are in the ratio 5 : 4 and its perimeter is 90 cm. Find its length and breadth.
Solution: Let the length and breadth of the rectangle be 5x and 4x respectively. ∴ 2(5x + 4x) = 90 ⇒ 18x = 90 ⇒ x = 5 Length of the rectangle is (5× 5) = 25 cm and breadth = (4 × 5) = 20 cm.(13) Name each of the following parallelograms.
(i) The diagonals are equal and the adjacent sides are unequal. Ans: Rectangle. (ii) The diagonals are equal and the adjacent sides are equal. Ans: Square. (iii) The diagonals are unequal and the adjacent sides are equal. Ans: Rhombus. (iv) All the sides are equal and one angle is 60 o . Ans: Rhombus. (v) All the sides are equal and angle is 90 o . Ans: Square. (vi) All the angles are equal and the adjacent sides are unequal. Ans: Rectangle.(14) Which of the following statements are true and which are false?
(i) The diagonals of a parallelogram are equal. ⇒ False (ii) The diagonals of a rectangle are perpendicular to each other. ⇒ False (iii) The diagonals of a rhombus are equal. ⇒ False (iv) Every rhombus is a kite. ⇒ False (v) Every rectangle is square. ⇒ False (vi) Every square is parallelogram. ⇒ True (vii) Every square is rhombus. ⇒ True (viii) Every rectangle is a parallelogram. ⇒ True (ix) Every parallelogram is rectangle. ⇒ False (x) Every rhombus is a parallelogram. ⇒ TrueConceptual Clarity: The solutions offer clear explanations of the properties and characteristics of parallelograms, helping students understand concepts such as parallel sides, equal opposite angles, and supplementary consecutive angles.
Application of Theorems: Students learn to apply important geometric theorems related to parallelograms, such as the Opposite Sides Theorem and the Opposite Angles Theorem, enhancing their problem-solving skills.
Step-by-Step Approach: Each problem is solved step-by-step, allowing students to follow the logical progression of the solution, making it easier to grasp complex concepts and methods.
Strengthening Analytical Skills: The exercise includes a variety of problems that require analytical thinking, enabling students to develop their ability to analyze and solve geometric problems efficiently.
Preparation for Exams: RS Aggarwal Solutions are aligned with the academic curriculum and examination patterns, providing students with practice questions that prepare them for exams and boost their confidence.
Building a Strong Foundation: By understanding parallelograms, students lay a strong foundation for studying more advanced geometric concepts, which will be beneficial in higher-level mathematics.
