In a parallelogram A B C D if ∠ A is 4 5 of ∠ B , then what is ∠ A ?

Let, A B C D is a parallelogram, where ∠ A = 4 5 ∠ B We know that, The adjacent angles of a parallelogram are supplementary. ∴ ∠ A + ∠ B = 180 ° ⇒ 4 5 ∠ B + ∠ B = 180 ° ⇒ 9 ∠ B 5 = 180 ° ⇒ 9 ∠ B = 900 ° ⇒ ∠ B = 900 ° 9 = 100 ° Now, ∠ A = 4 5 ∠ B ⟹ ∠ A = 4 5 × 100 ° ⟹ ∠ A = 80 ° Therefore, the required answer is ∠ A = 80 ° .

E M B I B E

Full Marks Mathematics 9>Chapter 8 - Quadrilaterals>TEST YOUR SKILLS>Q 22

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IMPORTANT

Earn 100

Is the statement: ''diagonals of a rhombus are equal and perpendicular to each other''
(i) False
(ii) True
(iii) Sometimes true and sometimes false.

Important Questions on Quadrilaterals

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9th CBSE

IMPORTANT

Full Marks Mathematics 9>Chapter 8 - Quadrilaterals>TEST YOUR SKILLS>Q 23

In the statement, ''If three angles of a quadrilateral $A B C D$ are equal, then it is a parallelogram.''

True, False, May or may not be true.

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9th CBSE

IMPORTANT

Full Marks Mathematics 9>Chapter 8 - Quadrilaterals>TEST YOUR SKILLS>Q 24

What do the two angles of a quadrilateral having a common arm are called?

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9th CBSE

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Full Marks Mathematics 9>Chapter 8 - Quadrilaterals>TEST YOUR SKILLS>Q 25

What do the two angles of a quadrilateral having no common arm are called?

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9th CBSE

IMPORTANT

Full Marks Mathematics 9>Chapter 8 - Quadrilaterals>TEST YOUR SKILLS>Q 26

Which of the following is true?
(i) The diagonals of a trapezium are always equal
(ii) A trapezium can be parallelogram but a parallelogram cannot be a trapezium.
(iii) A parallelogram can be a trapezium but a trapezium cannot be a parallelogram.

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9th CBSE

IMPORTANT

Full Marks Mathematics 9>Chapter 8 - Quadrilaterals>TEST YOUR SKILLS>Q 27

In a parallelogram