Advertisements
Advertisements
प्रश्न
The adjacent sides of a parallelogram are 21 cm and 28 cm. If it's one diagonal is 35 cm; find the area of the parallelogram.
Advertisements
उत्तर
First, we find the area of ΔABC.
Sides are, a = 28 cm
b = 35 cm
and c = 21 cm
S = `(a + b + c)/2`
= `(28 + 35 + 21)/2`
= `84/2 = 42` cm
area of ΔABD = `sqrt(S(S - a)(S - b)(S - c))`
= `sqrt(42(42 - 28)(42 - 35)(42 - 21))`
= `sqrt(42 xx 14 xx 7 xx 21)`
= `sqrt(2 xx 21 xx 2 xx 7 xx 7 xx 21)`
= `sqrt(2 xx 2 xx 21 xx 21 xx 7 xx 7)`
= `2 xx 21 xx 7`
= 294 cm2
∵ Diagonal of ||gm divides it into two equal parts.
∴ area of ||gm = `2 xx "area of ΔABC"`
= 2 × 294
= 588 cm2
APPEARS IN
संबंधित प्रश्न
A parallelogram has sides of 20 cm and 30 cm. If the distance between its shorter sides is 15 cm; find the distance between the longer sides.
Find the missing values.
| Base | Height | Area |
| 18 cm | 5 cm |
Find the missing values.
| Base | Height | Area |
| 8 cm | 56 sq.m |
A ground is in the shape of parallelogram. The height of the parallelogram is 14 metres and the corresponding base is 8 metres longer than its height. Find the cost of levelling the ground at the rate of ₹ 15 per sq.m
In a parallelogram the base is three times its height. If the height is 8 cm then the area is
Find the missing value:
| Base | Height | Area of parallelogram |
| 15.6 cm | ______ | 16.38 cm2 |
Observe the shapes 1, 2, 3 and 4 in the figures. Which of the following statements is not correct?
If the sides of a parallelogram are increased to twice its original lengths, how much will the perimeter of the new parallelogram?
To find area, any side of a parallelogram can be chosen as ______ of the parallelogram.
ABCD is a parallelogram in which AE is perpendicular to CD (see figure). Also AC = 5 cm, DE = 4 cm and area of ΔAED = 6 cm2. Find the perimeter and area of ABCD.
