Math Problem Statement

Show that the points (4, 0), (2, 1), and (-1,-5) are vertices of a right triangle. Find its area.

Solution

To show that the points (4,0)(4, 0), (2,1)(2, 1), and (1,5)(-1, -5) are vertices of a right triangle, we need to verify that the triangle formed by these points satisfies the Pythagorean theorem. We'll also find the area of the triangle.

Step 1: Calculate the distances between the points

We use the distance formula to find the lengths of the sides of the triangle:

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

  1. Distance between (4,0)(4, 0) and (2,1)(2, 1):

d1=(24)2+(10)2=(2)2+12=4+1=5d_1 = \sqrt{(2 - 4)^2 + (1 - 0)^2} = \sqrt{(-2)^2 + 1^2} = \sqrt{4 + 1} = \sqrt{5}

  1. Distance between (2,1)(2, 1) and (1,5)(-1, -5):

d2=(12)2+(51)2=(3)2+(6)2=9+36=45=35d_2 = \sqrt{(-1 - 2)^2 + (-5 - 1)^2} = \sqrt{(-3)^2 + (-6)^2} = \sqrt{9 + 36} = \sqrt{45} = 3\sqrt{5}

  1. Distance between (4,0)(4, 0) and (1,5)(-1, -5):

d3=(14)2+(50)2=(5)2+(5)2=25+25=50=52d_3 = \sqrt{(-1 - 4)^2 + (-5 - 0)^2} = \sqrt{(-5)^2 + (-5)^2} = \sqrt{25 + 25} = \sqrt{50} = 5\sqrt{2}

Step 2: Verify the Pythagorean theorem

The Pythagorean theorem states that for a right triangle:

Hypotenuse2=Side12+Side22\text{Hypotenuse}^2 = \text{Side}_1^2 + \text{Side}_2^2

Here, we compare the squares of the distances:

  • Hypotenuse=d3=52\text{Hypotenuse} = d_3 = 5\sqrt{2}
  • Side1=d2=35\text{Side}_1 = d_2 = 3\sqrt{5}
  • Side2=d1=5\text{Side}_2 = d_1 = \sqrt{5}

Now, check if:

(52)2=(35)2+(5)2(5\sqrt{2})^2 = (3\sqrt{5})^2 + (\sqrt{5})^2

Calculate each side:

  • (52)2=50(5\sqrt{2})^2 = 50
  • (35)2=45(3\sqrt{5})^2 = 45
  • (5)2=5(\sqrt{5})^2 = 5

Since:

50=45+550 = 45 + 5

The equation holds true, confirming that the points form a right triangle.

Step 3: Calculate the area of the right triangle

The area AA of a right triangle is given by:

A=12×base×heightA = \frac{1}{2} \times \text{base} \times \text{height}

Here, we can take (d_1 = \

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Coordinate Geometry
Pythagorean Theorem
Distance Formula
Triangle Properties

Formulas

Distance formula: \( d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2} \)
Pythagorean theorem: \( \text{Hypotenuse}^2 = \text{Side}_1^2 + \text{Side}_2^2 \)
Area of a triangle: \( A = \frac{1}{2} \times \text{base} \times \text{height} \)

Theorems

Pythagorean theorem

Suitable Grade Level

High School