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
An isosceles triangle has perimeter 30 cm and each of the equal sides is 12 cm. Find the area of the triangle.
Find the area of a triangle whose base and altitude are 5 cm and 4 cm respectively.
Find the area of a triangle whose sides are 3 cm, 4 cm and 5 cm respectively.
Some measures are given in the adjacent figure, find the area of ☐ABCD.
Find the areas of the given plot. (All measures are in metres.)
Determine whether the sets of points are collinear?
`(-1/2, 3), (-5, 6) and (-8, 8)`
If the points A(– 3, 9), B(a, b) and C(4, – 5) are collinear and if a + b = 1, then find a and b
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.
A field in the form of a parallelogram has sides 60 m and 40 m and one of its diagonals is 80 m long. Find the area of the parallelogram.
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.
