Triangle Side Analysis: Is 19+X = 7X+1 = 25-X an Equilateral Triangle?

Question

Given the size of the 3 sides of the triangle, is it an equilateral triangle?

19+X19+X19+XAAABBBCCC7X+125-X

Video Solution

Solution Steps

00:10 Let's check if the triangle is equilateral.
00:13 Assume the triangle is equilateral. First, we'll find the value of X. Then, we'll verify it.
00:19 Set the two sides equal to find X.
00:23 Now, solve for X. Isolate X on one side of the equation.
00:37 This is X when the sides are equal. Let's verify this assumption.
00:42 Substitute X back into each side. Check if all the sides are equal.
00:48 Here's the value of one side with X substituted in.
00:52 Now, substitute X into the second side.
00:56 Do the same for the third side. Yes, the triangle is equilateral!
01:01 And that's how we solve the problem. Great job!

Step-by-Step Solution

To solve this problem, we will follow these steps:

  • Step 1: Calculate when 19+X=7X+1 19 + X = 7X + 1 .
  • Step 2: Calculate when 7X+1=25X 7X + 1 = 25 - X .
  • Step 3: Calculate when 25X=19+X 25 - X = 19 + X .
  • Step 4: Check that these conditions are satisfied simultaneously for the triangle to be equilateral.

Step 1: Solve 19+X=7X+1 19 + X = 7X + 1 .

Rearranging terms, we get 191=7XX 19 - 1 = 7X - X .

This simplifies to 18=6X 18 = 6X , giving X=3 X = 3 .

Step 2: Solve 7X+1=25X 7X + 1 = 25 - X .

Rearranging terms, we get 7X+X=251 7X + X = 25 - 1 .

This simplifies to 8X=24 8X = 24 , giving X=3 X = 3 .

Step 3: Solve 25X=19+X 25 - X = 19 + X .

Rearranging terms, we get 2519=X+X 25 - 19 = X + X .

This simplifies to 6=2X 6 = 2X , giving X=3 X = 3 .

We find that all conditions are satisfied when X=3 X = 3 , and thus all sides are equal at this value.

The side lengths with X=3 X = 3 are:

  • 19+3=22 19 + 3 = 22
  • 7(3)+1=22 7(3) + 1 = 22
  • 253=22 25 - 3 = 22

All sides become equal with X=3 X = 3 , thus the triangle is equilateral.

The solution to the problem is Yes.

Answer

Yes