Advertisements
Advertisements
Question
Find the area of an equilateral triangle having perimeter of 18cm.
Solution
We know that, Perimeter of an equilateral triangle(P) of side a = 3a
Here, P = 18cm
⇒ side of the equilateral triangle is = 6cm
Area of an equilateral triangle (A) of side is A = `sqrt(3)/(4)"a"^2`
⇒ A = `sqrt(3)/(4)(6)^2`
⇒ `sqrt(3)/(4)(36)`
⇒ `9sqrt(3)`
Area of an equilateral triangle(A) of side 6cm is `9sqrt(3)"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 perimeter of an equilateral triangle whose area is `16sqrt(3)"cm"`.
Find the area of the shaded region in the figure as shown, in which DPQS is an equilateral triangle and ∠PQR = 90°.
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.
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 72cm and the base is 20cm.
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
The cross-section of a canal is a trapezium in shape. If the canal is 10m wide at the top, 6m wide at the bottom and the area of cross-section is 72 sq.m, determine its depth.
In an isosceles triangle, two angles are always ______.
