Math Problem Statement

A manufacturer cuts a piece of metal for a microscope. The resulting piece of metal can be represented in a coordinate plane by a triangle with vertices A(0,0), B(3,8), and C(6,0). One unit in the coordinate plane represents one millimeter. Prove that triangle ABC is isosceles. Find the exact length of each side.

Solution

Let's solve the problem. We are tasked with finding the exact lengths of each side of the triangle ABC\triangle ABC, given its vertices:

  • A(0,0)A(0, 0),
  • B(3,8)B(3, 8),
  • C(6,0)C(6, 0).

Afterward, we will verify that ABC\triangle ABC is isosceles by comparing the side lengths.

Step 1: Calculate each side length using the distance formula

The distance formula between two points (x1,y1)(x_1, y_1) and (x2,y2)(x_2, y_2) is: d=(x2x1)2+(y2y1)2d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}

Length of ABAB:

AB=(30)2+(80)2=32+82=9+64=73mm.AB = \sqrt{(3 - 0)^2 + (8 - 0)^2} = \sqrt{3^2 + 8^2} = \sqrt{9 + 64} = \sqrt{73} \, \text{mm}.

Length of BCBC:

BC=(63)2+(08)2=(63)2+(8)2=32+82=73mm.BC = \sqrt{(6 - 3)^2 + (0 - 8)^2} = \sqrt{(6 - 3)^2 + (-8)^2} = \sqrt{3^2 + 8^2} = \sqrt{73} \, \text{mm}.

Length of ACAC:

AC=(60)2+(00)2=62=6mm.AC = \sqrt{(6 - 0)^2 + (0 - 0)^2} = \sqrt{6^2} = 6 \, \text{mm}.

Step 2: Verify if ABC\triangle ABC is isosceles

An isosceles triangle has at least two equal side lengths. From the calculations:

  • AB=73AB = \sqrt{73},
  • BC=73BC = \sqrt{73},
  • AC=6AC = 6.

Since AB=BCAB = BC, ABC\triangle ABC is isosceles.

Final Answer:

  • AB=73mmAB = \sqrt{73} \, \text{mm},
  • BC=73mmBC = \sqrt{73} \, \text{mm},
  • AC=6mmAC = 6 \, \text{mm}.

Because AB=BC,ABC is isosceles.\text{Because } AB = BC, \triangle ABC \text{ is isosceles}.


Would you like further explanation on the distance formula or the verification process?

Here are five related questions:

  1. What is the general formula for verifying an equilateral triangle?
  2. How does one calculate the perimeter of ABC\triangle ABC?
  3. Can you calculate the area of ABC\triangle ABC?
  4. How would you determine if ABC\triangle ABC is a right triangle?
  5. What if A,B,CA, B, C were given as 3D points? How would the calculations change?

Tip: Always check for at least two equal sides to confirm if a triangle is isosceles.

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Math Problem Analysis

Mathematical Concepts

Geometry
Coordinate Geometry
Triangles

Formulas

Distance formula: d = sqrt((x2 - x1)^2 + (y2 - y1)^2)

Theorems

Isosceles Triangle Theorem

Suitable Grade Level

Grades 8-10