equilaterial triangle question

[spoog74]

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what is the perimeter of a triangle in cm of its height is 5 cm?

Someone shed some light onthis question plz

 

[bharat008]

what is the perimeter of a triangle in cm of its height is 5 cm?

Someone shed some light onthis question plz

Is the answer 15cm..

 

[PhansterZ]

what is the perimeter of a triangle in cm of its height is 5 cm?

Someone shed some light onthis question plz

To get the perimeter of the triangle, figure out one of the sides.
Each angle of the equilateral triangle is 60 degrees, so if you draw out the triangle, you can set up equation to have sin60 = height/side.

sin60 = 5/side

side= 5/ (root3/2)
side = 10/root3
side = 10root3/3


perimeter = 3(side) = 10root3

 

[spoog74]

To get the perimeter of the triangle, figure out one of the sides.
Each angle of the equilateral triangle is 60 degrees, so if you draw out the triangle, you can set up equation to have sin60 = height/side.

sin60 = 5/side

side= 5/ (root3/2)
side = 10/root3
side = 10root3/3


perimeter = 3(side) = 10root3

i dont understand, they gave us the fact that it is an equilateral triangle, why do we need to figure out any more sides? They give us 5 was the height, thus why wouldnt it be 15 ? Why find out the other sides when its equilateral?

 

[PhansterZ]

i dont understand, they gave us the fact that it is an equilateral triangle, why do we need to figure out any more sides? They give us 5 was the height, thus why wouldnt it be 15 ? Why find out the other sides when its equilateral?

Oh, I see. I think you're confused over what the side is and the height. They aren't the same thing. I've attached a picture to make it clearer on what they mean by the side and the height. This is the triangle I used to set up my equation.

For an equilateral triangle, the sides are the same, but not the height.

 

[JamesBourne]

i dont understand, they gave us the fact that it is an equilateral triangle, why do we need to figure out any more sides? They give us 5 was the height, thus why wouldnt it be 15 ? Why find out the other sides when its equilateral?

Some misconception here, the height of an equilateral triangle is not the same as side length, all three sides are equal in length, but the height is different. Try dividing the triangle in half by drawing in the height and you will have two triangles of 30-60-90 degrees thus making all three sides' length different, and this is why we are using sin of 60 to figure out the side length. Hope it makes sense for you.

 

[spoog74]

Some misconception here, the height of an equilateral triangle is not the same as side length, all three sides are equal in length, but the height is different. Try dividing the triangle in half by drawing in the height and you will have two triangles of 30-60-90 degrees thus making all three sides' length different, and this is why we are using sin of 60 to figure out the side length. Hope it makes sense for you.

ahh ok. Got it. Thanks all !