The lengths of the diagonals of a rhombus are
(i) 16 cm and 12 cm
(ii) 30 cm and 40 cm
Find the perimeter of the rhombus.
Answers
✬ (i) Perimeter = 40 cm ✬
✬ (ii) Perimeter = 100 cm ✬
Step-by-step explanation:
Given:
- (1) Length of diagonals of rhombus are 16 & 12 cm respectively.
To Find:
- What is the perimeter of rhombus ?
Solution: Let ABCD be a rhombus where
- AB || DC & BC || AD
- AC = 16 cm ( Diagonal )
- BD = 12 cm ( Diagonal )
[ The diagonals of a rhombus bisect each other perpendicularly i.e at 90° ]
So,
➯ AO = OC = 1/2(AC)
➯ AO = OC = 1/2(16)
➯ AO = OC = 8 cm
and
➯ BO = OD = 1/2(BD)
➯ BO = OD = 1/2(12)
➯ BO = OD = 6 cm
Now, in right angled ∆AOB
- AB = Hypotenuse
- BO = Base
- AO = Perpendicular
- ∠AOB = 90°
Applying Pythagoras Theorem:
★ Pythagoras Theorem : H² = P² + B² ★
AB² = AO² + BO²
AB² = 8² + 6²
AB² = 64 + 36
AB = √100 = 10
Hence,
=> Perimeter of rhombus = 4(Side)
=> Perimeter = 4(10) = 40 cm
_____________________
Now in same rhombus taking diagonals as 30 cm and 40 cm.
➯ AO = OC = 1/2(AC)
➯ AO = OC = 1/2(30)
➯ AO = OC = 15 cm
and
➯ BO = OD = 1/2(BD)
➯ BO = OD = 1/2(40)
➯ BO = OD = 20 cm
In ∆AOB ,
- AO = Perpendicular , BO = Base , AB = Hypotenuse
Applying Pythagoras Theorem:
AB² = AO² + BO²
AB² = 15² + 20²
AB² = 225 + 400
AB = √625
AB = 25 cm
Hence,
=> Perimeter of rhombus = 4(25) = 100 cm
✬ (i) Perimeter = 40 cm ✬
✬ (ii) Perimeter = 100 cm ✬
Given:
(1) Length of diagonals of rhombus are 16 & 12 cm respectively.
To Find:
What is the perimeter of rhombus ?
Solution: Let ABCD be a rhombus where
AB || DC & BC || AD
AC = 16 cm ( Diagonal )
BD = 12 cm ( Diagonal )
[ The diagonals of a rhombus bisect each other perpendicularly i.e at 90° ]
So,
➯ AO = OC = 1/2(AC)
➯ AO = OC = 1/2(16)
➯ AO = OC = 8 cm
and
➯ BO = OD = 1/2(BD)
➯ BO = OD = 1/2(12)
➯ BO = OD = 6 cm
Now, in right angled ∆AOB
AB = Hypotenuse
BO = Base
AO = Perpendicular
∠AOB = 90°
Applying Pythagoras Theorem:
★ Pythagoras Theorem : H² = P² + B² ★
⟹ AB² = AO² + BO²
⟹ AB² = 8² + 6²
⟹ AB² = 64 + 36
⟹ AB = √100 = 10
Hence,
=> Perimeter of rhombus = 4(Side)
=> Perimeter = 4(10) = 40 cm
_____________________
Now in same rhombus taking diagonals as 30 cm and 40 cm.
➯ AO = OC = 1/2(AC)
➯ AO = OC = 1/2(30)
➯ AO = OC = 15 cm
and
➯ BO = OD = 1/2(BD)
➯ BO = OD = 1/2(40)
➯ BO = OD = 20 cm
In ∆AOB ,
AO = Perpendicular , BO = Base , AB = Hypotenuse
Applying Pythagoras Theorem:
⟹ AB² = AO² + BO²
⟹ AB² = 15² + 20²
⟹ AB² = 225 + 400
⟹ AB = √625
⟹ AB = 25 cm
Hence,
=> Perimeter of rhombus = 4(25) = 100 cm