18. The length and breadth of a
rectangle is in the ratio 5: 4. If its
perimeter is 90 m, then its area
will be : INET & HAZ., 2006-07]
(a) 500 m2
(b) 360 m2
th (c) 540 m2 (d) 900 m2
2:19. If the hypotenuse of a right triangle
is 5 cm and base is 4 cm, then find
its height.
[NET & HAZ., 2006-07)
(a) 6 cm
(b) 3 cm
(c) 4 cm (d) 8 cm
Answers
Solution
Given
Length be 5x
breadth be 4x
A/Q
2(5x+4x) = 90m
2×9x = 90m
18x = 90m
X = 90m ÷18
X = 5m
Length = 5m×5 =25 m
Breadth = 5m ×4 =20 m
Area of rectangle = Length ×breadth
= 25m × 20m
500m square
hence, area of rectangle v 500 metre square
Question~
The length and breadth of a rectangle is in the ratio 5:4. If its perimeter is 90 m, then its area will be :
(a) 500 m²
(b) 360 m²
(c) 540 m²
(d) 900 m²
--------------------
Given :
- The ratio of Length and Breadth = 5:4
- The perimeter of Rectangle = 90 m
To find :
- the area
Solution :
⇒ Let the length be 5x and breadth be 4x.
Perimeter of Rectangle = 2 (l + b)
90 = 2 (5x + 4x)
90 = 2 (9x)
90 = 18x
x = 90/18
= 5
→ Length of Rectangle = 5x
= 5 × 5
= 25 m
→ Breadth of Rectangle = 4x
= 5 × 4
= 20 m
⇒ Now, let's find the Area.
Area = l × b
= 25 × 20
= 500 m²
- Therefore, option (a) 500 m² is the right answer.
____________________
Question~
If the hypotenuse of a right triangle is 5 cm and base is 4 cm, then find its height.
(a) 6 cm
(b) 3 cm
(c) 4 cm
(d) 8 cm
--------------------
Given :
- Hypotenuse = 5 cm
- Base = 4 cm
To find :
- the height
Solution :
⇒ Let's find the Height, by using the Pythagoras theorem.
= (base)² + (height)² = (hypotenuse)²
= (4)² + (height)² = 5²
Height = √(5)²- (4)²
= √25 - 16
= √9
= 3 cm
- Therefore, the height of the right triangle is 3 cm.