Question

in parallelogram ABCD , angle A = 3 angle B. find all the angles of the parallelogram . in the same parallelogram , if AB = (5x -7) cm and CD = (3x +1) cm, find the length of CD.​

Answer 1

Answer:

given - AB=5x-7 cm

CD=3x+1 cm

to find- length of CD

Solution -

opposite side of parallelogram are equal so AB=CD

SO 5x-7 = 3x+1

5x-3x = 1+7

2x = 8

x = 8/2

x=4

so CD = 3x+1

3(4)+1

12+1

13 ans

Answer 2

☆ Given :

$\:$

• Angle (A) = 3 (∠B)

• AB = (5x - 7)

• CD = (3x + 1)

$\:$

☆ On Solving :

$\:$

• Finding Angles :

$\:$

∠A = ∠B [ Corresponding angles ]

∠D = ∠A [ Transversal ]

➪ ∠B = ∠C [ Transversal ]

➪ ∠D = ∠C [ Corresponding angles ]

∴ ∠A = ∠B = ∠C = ∠D = 3(∠B)

$\:$

• Now Finding CD :

$\:$

☕︎ Taking : AB = CD

➪ 5x - 7 = 3x + 1

• On Transposing The Terms :

➪ 5x - 3x = 7 + 1

➪ 2x = 8

$➪ \large\mathrm{ \: \: x \: = \dfrac{8}{2} }$

∴ x = 4

$\:$

• Now ,

$\:$

5x - 7 = 3x + 1

➪ 5(4) - 7 = 3(4) + 1

➪ 20 - 7 = 12 + 1

➪ 13 = 13

∴ L.H.S = R.H.S

• Hence Proved

= CD = 13cm