Math Problem Statement

Show that the points (-2, 3), (8, 3) and (6, 7) are the vertices of a right-angled triangle.

Solution

The problem asks us to prove that the points (2,3)(-2, 3), (8,3)(8, 3), and (6,7)(6, 7) are the vertices of a right-angled triangle. To do this, we can use the distance formula to calculate the lengths of the sides of the triangle and then apply the Pythagorean theorem.

Step 1: Calculate the distances between each pair of points (the sides of the triangle)

The distance formula is:

d=(x2x1)2+(y2y1)2d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}

Distance between (2,3)(-2, 3) and (8,3)(8, 3):

d1=(8(2))2+(33)2=(8+2)2=102=10d_1 = \sqrt{(8 - (-2))^2 + (3 - 3)^2} = \sqrt{(8 + 2)^2} = \sqrt{10^2} = 10

Distance between (8,3)(8, 3) and (6,7)(6, 7):

d2=(68)2+(73)2=(2)2+42=4+16=204.47d_2 = \sqrt{(6 - 8)^2 + (7 - 3)^2} = \sqrt{(-2)^2 + 4^2} = \sqrt{4 + 16} = \sqrt{20} \approx 4.47

Distance between (6,7)(6, 7) and (2,3)(-2, 3):

d3=(6(2))2+(73)2=(6+2)2+42=82+42=64+16=808.94d_3 = \sqrt{(6 - (-2))^2 + (7 - 3)^2} = \sqrt{(6 + 2)^2 + 4^2} = \sqrt{8^2 + 4^2} = \sqrt{64 + 16} = \sqrt{80} \approx 8.94

Step 2: Check if the Pythagorean theorem holds

The Pythagorean theorem states that for a right-angled triangle, the sum of the squares of the two shorter sides must equal the square of the longest side. Let's check this condition.

  • The longest side is d1=10d_1 = 10.
  • Check if d12=d22+d32d_1^2 = d_2^2 + d_3^2: 102=4.472+8.94210^2 = 4.47^2 + 8.94^2 100=20+80100 = 20 + 80 100=100100 = 100

Since the Pythagorean theorem holds, the points indeed form a right-angled triangle.

Would you like a further explanation or clarification on this solution?

Here are some related questions to explore:

  1. How can the distance formula be derived from the Pythagorean theorem?
  2. Can you prove that another set of points forms a right-angled triangle using the same method?
  3. How do you find the area of a triangle when you know the coordinates of its vertices?
  4. What other methods can be used to prove that a triangle is right-angled?
  5. How does the Pythagorean theorem generalize to 3-dimensional space?

Tip: Always double-check the distance calculations when working with coordinate geometry problems to avoid small errors.

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Math Problem Analysis

Mathematical Concepts

Coordinate Geometry
Triangles
Right-angled Triangles

Formulas

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

Theorems

Pythagorean Theorem

Suitable Grade Level

Grades 9-10