Advertisements
Advertisements
Question
Find the area of an equilateral triangle having perimeter of 18cm.
Advertisements
Solution
Find side length
`"Side" = "Perimeter"/3 = 18/3 = 6 cm`
`"Area" = sqrt3/4 xx a^2`
a = side length.
`Area = sqrt3/4 xx (6^2) = sqrt3/4 xx 36 = 9sqrt3 cm^2`
`9sqrt3 = 9 xx 1.732 = 15.588 cm^2`
`Area = 9sqrt3 cm^2 = 15.6 cm^2`
APPEARS IN
RELATED QUESTIONS
Find the area of an isosceles triangle ABC in which AB = AC = 6 cm, ∠A = 90°. Also, find the length of perpendicular from A to BC.
Find the area of an equilateral triangle of side 20 cm.
The area of an equilateral triangle is numerically equal to its perimeter. Find the length of its sides, correct two decimal places.
In a right-angled triangle PQR right-angled at Q, QR = x cm, PQ = (x + 7) cm and area = 30 cm2. Find the sides of the triangle.
In a right-angled triangle ABC, if ∠B = 90°, AB - BC = 2 cm; AC - BC = 4 and its perimeter is 24 cm, find the area of the triangle.
Find the area of an isosceles triangle whose perimeter is 50cm and the base is 24cm.
Each equal side of an isosceles triangle is 3cm less than the unequal side. The height of the perpendicular from the vertex to the unequal side is 3cm less than the equal side. If the area of the isosceles triangle is 108cm2, find the perimeter of the triangle.
A wire when bent in the form of a square encloses an area of 16 cm2. Find the area enclosed by it when the same wire is bent in the form of a rectangle whose sides are in the ratio of 1 : 3
If in an isosceles triangle, each of the base angles is 40°, then the triangle is ______.
In an isosceles triangle, angles opposite to equal sides are ______.
