CLASS IX MATHS 6 areas of parallelogram and triangles

1. Area of Parallelograms

2. Goal
To show that the area of parallelograms is
the product of base and height

3. Key Vocabulary
Base of a parallelogram
Height of a parallelogram
Parallelogram

4. Parallelogram
A parallelogram is a quadrilateral where
the opposite sides are equal and
parallel.
A rectangle is a type of parallelogra.

5. The Base of a Parallelogram
Either pair of parallel sides of a parallelogram
are called the bases of the parallelogram.
base
base

6. The Height of a Parallelogram
The shortest distance (perpendicular distance)
between the bases of a parallelogram is called the
height of the parallelogram.
The height of the parallelogram is always
perpendicular to the bases.

7. What is the area
of this parallelogram?
b=base
h=height
Area of Parallelogram

8. What is the area
of this parallelogram?
CUT HERE!
b=base
h=height
Area of Parallelogram

9. What is the area
of this parallelogram?
MOVE TO HERE!
b=base
h=height
Area of Parallelogram

10. It’s the same as
the area of this rectangle
h=height
b=base
Area of Parallelogram

11. Arearectangle= base x height
(perpendicular height h)
h=height
b=base
Area of Parallelogram

12. Areaparallelogram = base x height
(perpendicular height h)
b=base
h=height
Area of Parallelogram

13. b
h
Area of Parallelogram
Words: Area
=(base)(height)
Symbols: A = bh
Very Important: The height must be perpendicular to the base.

14. Find the Area of a ParallelogramExample 1
Find the area of the parallelogram.
SOLUTION
Use the formula for the area of a parallelogram.
Substitute 9 for b and 6 for h.
A = bh Formula for the area of a parallelogram
= (9)(6) Substitute 9 for b and 6 for h.
= 54 Multiply.
The parallelogram has an area of 54
square meters.
ANSWER

15. Find the Height of a ParallelogramExample 2
Find the height of the parallelogram
given that its area is 78 square
meter.
SOLUTION
A = bh Formula for the area of a parallelogram
78 = 12h Substitute 78 for A and 12 for b.
6.5 = h Divide each side by 12.
The parallelogram has a height of 6.5 m.ANSWER

16. Find the area of the parallelogram.
1.
ANSWER 77 mm2
ANSWER 196 m2

17. In Exercises 4–6, A gives the area of the parallelogram.
Find the missing measure.
ANSWER h = 6 m.
ANSWER b = 6 m
ANSWER h = 4 cm
4. A = 72 m2
5. A = 30 m2
6. A = 28 cm2

18. THANK YOU