Advertisements
Advertisements
प्रश्न
Find the area of a triangle two sides of which are 18 cm and 10 cm and the perimeter is 42 cm.
Advertisements
उत्तर
Let the third side of the triangle be x.
The perimeter of the given triangle = 42 cm
18 cm + 10 cm + x = 42
x = 14 cm
s = `"Perimeter"/2`
= `42/2 cm`
= 21 cm
By Heron's formula,
Area of a triangle = `sqrt(s(s-a)(s-b)(s-c))`
Area of the given triangle = `(sqrt(21(21-18)(21-10)(21-14)))cm^2`
= `(sqrt(21(3)(11)(7)))cm^2`
= `21sqrt11 cm^2`
APPEARS IN
संबंधित प्रश्न
A triangle has sides 35 cm, 54 cm and 61 cm long. Find its area. Also, find the smallest of its altitudes ?
A rhombus sheet, whose perimeter is 32 m and whose one diagonal is 10 m long, is painted on both sides at the rate of Rs 5 per m2. Find the cost of painting.
The adjacent sides of a parallelogram ABCD measure 34 cm and 20 cm, and the diagonal AC measures 42 cm. Find the area of the parallelogram.
Find the area of the triangle formed by the points
(–10, –4), (–8, –1) and (–3, –5)
The area of a triangle is 5 sq. units. Two of its vertices are (2, 1) and (3, −2). The third vertex is (x, y) where y = x + 3. Find the coordinates of the third vertex.
An isosceles right triangle has area 8 cm2. The length of its hypotenuse is ______.
The perimeter of a triangular field is 420 m and its sides are in the ratio 6 : 7 : 8. Find the area of the triangular field.
A rhombus shaped sheet with perimeter 40 cm and one diagonal 12 cm, is painted on both sides at the rate of Rs 5 per m2. Find the cost of painting.
The perimeter of a triangle is 50 cm. One side of a triangle is 4 cm longer than the smaller side and the third side is 6 cm less than twice the smaller side. Find the area of the triangle.
A field is in the shape of a trapezium having parallel sides 90 m and 30 m. These sides meet the third side at right angles. The length of the fourth side is 100 m. If it costs Rs 4 to plough 1 m2 of the field, find the total cost of ploughing the field.
