The ends of the hypotenuse of a right-angle triangle are [tex]\([0, 6]\)[/tex] and [tex]\([6, 0]\)[/tex]. Find the equation of the locus of its third vertex.

Solution:
Let [tex]\( P = [x, y] \)[/tex] be the third vertex.



Answer :

Sure, let's solve the problem!

We are given the endpoints of the hypotenuse of a right-angle triangle, which are [tex]\((0, 6)\)[/tex] and [tex]\((6, 0)\)[/tex]. We need to determine the equation of the locus of the third vertex, [tex]\((x, y)\)[/tex], of the right-angle triangle.

The key idea here is that the third vertex, [tex]\((x, y)\)[/tex], is equidistant from both endpoints of the hypotenuse [tex]\((0, 6)\)[/tex] and [tex]\((6, 0)\)[/tex]. This is because the third vertex is at the right angle to the hypotenuse, forming two congruent right triangles.

We will use the property that for any point [tex]\((x, y)\)[/tex] on the locus, the distances to the points [tex]\((0, 6)\)[/tex] and [tex]\((6, 0)\)[/tex] must be equal. This allows us to set up the equation as follows:

### Step-by-step Solution:

1. Express the distances using the distance formula:

The distance between [tex]\((x, y)\)[/tex] and [tex]\((0, 6)\)[/tex] is:
[tex]\[ \text{Distance}_1 = \sqrt{(x - 0)^2 + (y - 6)^2} \][/tex]

The distance between [tex]\((x, y)\)[/tex] and [tex]\((6, 0)\)[/tex] is:
[tex]\[ \text{Distance}_2 = \sqrt{(x - 6)^2 + (y - 0)^2} \][/tex]

2. Set up the equation stating these distances are equal:

[tex]\[ \sqrt{(x - 0)^2 + (y - 6)^2} = \sqrt{(x - 6)^2 + (y - 0)^2} \][/tex]

3. Square both sides to eliminate the square roots:

[tex]\[ (x - 0)^2 + (y - 6)^2 = (x - 6)^2 + (y - 0)^2 \][/tex]

4. Simplify the equation:

[tex]\[ x^2 + (y - 6)^2 = (x - 6)^2 + y^2 \][/tex]

5. Distribute and expand both sides:

[tex]\[ x^2 + y^2 - 12y + 36 = x^2 - 12x + 36 + y^2 \][/tex]

6. Cancel out common terms on both sides:

Subtract [tex]\(x^2 + y^2 + 36\)[/tex] from both sides:

[tex]\[ -12y = -12x \][/tex]

7. Solve for [tex]\(y\)[/tex]:

Dividing both sides of the equation by [tex]\(-12\)[/tex], we get:

[tex]\[ y = x \][/tex]

### Conclusion:

The equation of the locus of the third vertex of the right-angle triangle is:

[tex]\[ y = x \][/tex]

Thus, the third vertex must lie on the line [tex]\(y = x\)[/tex] to maintain the right-angle property with the given hypotenuse endpoints [tex]\((0, 6)\)[/tex] and [tex]\((6, 0)\)[/tex].