An equilateral triangle ABC is inscribed in circle ,If length of arc ABC is 24, What is approximate diameter.
A 11
B 13
C 15
D 22
E 25
Diameter
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As triangle ABC is equilateral, arc ABC is 2/3 of the circumference of the circle.B166418 wrote:An equilateral triangle ABC is inscribed in circle ,If length of arc ABC is 24, What is approximate diameter.
A 11
B 13
C 15
D 22
E 25
Hence, circumference of the circle = 24*3/2 = 36
Hence, diameter of the circle = 36/π = Slightly less than 36/3 ≈ 11
The correct answer is A.
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B166418
The ARC ABC will include all the three vertices of the triangle. Hence, Arc ABC will be 2/3 of the total circumference of the circle.
What you have considered will be any of the arcs AB, BC or CA.
also since triangle ABC is equilateral then the arcs AB, BC and CA will be equal.
So arc ABC = arc AB + arc BC
Hope this helps.
The ARC ABC will include all the three vertices of the triangle. Hence, Arc ABC will be 2/3 of the total circumference of the circle.
What you have considered will be any of the arcs AB, BC or CA.
also since triangle ABC is equilateral then the arcs AB, BC and CA will be equal.
So arc ABC = arc AB + arc BC
Hope this helps.
B166418 wrote:An equilateral triangle ABC is inscribed in circle ,If length of arc ABC is 24, What is approximate diameter.
A 11
B 13
C 15
D 22
E 25
As triangle ABC is equilateral, arc ABC is 2/3 of the circumference of the circle.
Arc ABC = 2/3 * Circumference
24 = 2/3 * Circumference
Circumference = 36
Circumference = 2* pi*r
2* pi*r = 36
Diameter = 2 *r
=> diameter * pi = 36
=> diameter = 36/pi
=> diameter = 36/3 (pi is 22/7 which is approximately 3)
Hence, diameter of the circle = 36/π = Slightly less than 36/3 ≈ 11
The correct answer is A.
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B166418 wrote:Hi Kaustubh..
Is there any other way to solve this question apart from
length of arc = circumfrence of circle * Q\360
so here Q is 240 ?
Nice question, frankly the method that we are using seems to be the quickest approach. But I am working on another approach too (only after you asked). But let me tell you, things will get more complicated.
However, if you draw the figure for the question, you can just solve by looking at it. There is no need to write anything.
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Please have a look at this approach, nothing new, just a modification of the original approach.
we know that arc ABC = 24
also since triangle ABC is equilateral. all the three arcs are equal hence for arc AB
we solve
(120/360)*pi*D=12
solve this and you will get D~11
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The day you will realise that "ITS NOW OR NEVER".B166418 wrote:Here's d missing link
I solved this question by this method but took length of arc as given i.e 24 .
When I will stop doing silly mistakes
or
"Today will be that day
Not tomorrow, not next week but right now, right here"