each side of an equilateral triangle is 6cm. find the length of its altitudes.
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Answered by
6
Hi Mate!!!!
let the length of altitude be x
By Pythagoras theorem
( 6 )² = ( 3 )² + ( x )²
x² = 25
x = √ 25 or x = -√ 25
x = 5 or x = -5
x = -5 is rejected becoz length can't be -ive
so, length of altitude is 5cm
let the length of altitude be x
By Pythagoras theorem
( 6 )² = ( 3 )² + ( x )²
x² = 25
x = √ 25 or x = -√ 25
x = 5 or x = -5
x = -5 is rejected becoz length can't be -ive
so, length of altitude is 5cm
Anonymous:
sorry ......x² = 27 ........x = √27 .... x = 3√3
Answered by
10
hey mate here's ur answer
given :
each side of eq. ∆ ABC = 6 cm
let's draw an altitude AD on side BC.
now area of ∆ ABC = √3/4(side)²
= √3/4(6)²
= √3/4*36
= 9√3 cm²
now area of ∆ ABD = 1/2 area of ∆ ABC
=> 1/2*b*h = 9√3/2
=> 1/2*3*h = 9√3/2
=> h = (9√3/2)*(2/3)
=> h = 3√3
so, altitude of ∆ = 3√3 cm
alternatively :
By using Pythagoras theorem,
AB² = BD² + AD²
6² = 3² + AD²
AD² = 36 - 9
AD² = 27
AD = 3√3
given :
each side of eq. ∆ ABC = 6 cm
let's draw an altitude AD on side BC.
now area of ∆ ABC = √3/4(side)²
= √3/4(6)²
= √3/4*36
= 9√3 cm²
now area of ∆ ABD = 1/2 area of ∆ ABC
=> 1/2*b*h = 9√3/2
=> 1/2*3*h = 9√3/2
=> h = (9√3/2)*(2/3)
=> h = 3√3
so, altitude of ∆ = 3√3 cm
alternatively :
By using Pythagoras theorem,
AB² = BD² + AD²
6² = 3² + AD²
AD² = 36 - 9
AD² = 27
AD = 3√3
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