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.
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 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.
Find the base of an isosceles triangle whose area is 192cm2 and the length of one of the equal sides is 20cm.
A chessboard contains 64 equal square and the area of each square is 6.25cm2. A 2cm wide border is left inside of the board. Find the length of the side of the chessboard.
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 ______.
In an isosceles triangle, angles opposite to equal sides are ______.
Two line segments are congruent, if they are of ______ lengths.
