Find Type of Triangle Given r1-r2-r3

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In summary, the problem is asking for the type of triangle when r=r1-r2-r3, with r1,r2,r3 representing ex-radii. Using the fact that 4R = r1+r2+r3-r and r2+r3 = 2R, we can express r2 and r3 in terms of R and the sines and cosines of the three angles of the triangle. This can help us determine the type of triangle.
  • #1
utkarshakash
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Homework Statement


If in any triangle r=r1-r2-r3, then which type of triangle is it?
r1,r2,r3 denotes ex-radii.

The Attempt at a Solution



4R = r1+r2+r3-r

r2+r3 = 2R

I can't figure out what to do next.
 
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  • #2
What are ex-radii? I've never heard that term before. Also, what are ##r## and ##R## supposed to denote?
 
  • #3
vela said:
What are ex-radii? I've never heard that term before. Also, what are ##r## and ##R## supposed to denote?

Less encountered in geometry problems but they do exist. :)

http://en.wikipedia.org/wiki/Incircle_and_excircles_of_a_triangle

utkarshakash said:

Homework Statement


If in any triangle r=r1-r2-r3, then which type of triangle is it?
r1,r2,r3 denotes ex-radii.

The Attempt at a Solution



4R = r1+r2+r3-r

r2+r3 = 2R

I can't figure out what to do next.

Hi utkarshakash! :)

You are almost there. Can you express ##r_2## and ##r_3## in terms of R, the sines and cosines of three angles of the triangle?
 
  • #4

1. What is a triangle?

A triangle is a three-sided polygon that is formed by connecting three non-collinear points.

2. What is the difference between r1, r2, and r3 in a triangle?

In a triangle, r1, r2, and r3 refer to the lengths of the three sides. They are usually labeled in alphabetical order, with r1 being the shortest side and r3 being the longest side.

3. How do you find the type of triangle given r1, r2, and r3?

The type of triangle can be determined by comparing the lengths of the three sides. If r1 = r2 = r3, then the triangle is an equilateral triangle. If only two sides are equal, then the triangle is an isosceles triangle. If all three sides are different, then the triangle is a scalene triangle.

4. What is the Pythagorean theorem and how is it related to finding the type of triangle?

The Pythagorean theorem states that in a right triangle, the square of the length of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the other two sides. This theorem is often used to determine if a triangle is a right triangle, as well as to find the lengths of the sides of a right triangle.

5. Can a triangle have sides with negative lengths?

No, a triangle cannot have sides with negative lengths. The lengths of the sides must be positive numbers in order to form a valid triangle.

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