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The coordinates of the middle points of ...

The coordinates of the middle points of the sides of a triangle are (4, 2), (3, 3) and (2, 2), then coordinates of centroid are

A

(3, 7/3)

B

(3, 3)

C

(4, 3)

D

(3, 4)

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To find the coordinates of the centroid of a triangle given the midpoints of its sides, we can follow these steps: ### Step 1: Set Up the Midpoint Equations Given the midpoints of the sides of the triangle: - Midpoint of AB: \( D(4, 2) \) - Midpoint of BC: \( E(3, 3) \) - Midpoint of AC: \( F(2, 2) \) Let the vertices of the triangle be \( A(x_1, y_1) \), \( B(x_2, y_2) \), and \( C(x_3, y_3) \). From the midpoint formula, we can set up the following equations: 1. For midpoint \( D \): \[ \frac{x_1 + x_2}{2} = 4 \quad \text{and} \quad \frac{y_1 + y_2}{2} = 2 \] This gives us: \[ x_1 + x_2 = 8 \quad \text{(Equation 1)} \] \[ y_1 + y_2 = 4 \quad \text{(Equation 2)} \] 2. For midpoint \( E \): \[ \frac{x_2 + x_3}{2} = 3 \quad \text{and} \quad \frac{y_2 + y_3}{2} = 3 \] This gives us: \[ x_2 + x_3 = 6 \quad \text{(Equation 3)} \] \[ y_2 + y_3 = 6 \quad \text{(Equation 4)} \] 3. For midpoint \( F \): \[ \frac{x_1 + x_3}{2} = 2 \quad \text{and} \quad \frac{y_1 + y_3}{2} = 2 \] This gives us: \[ x_1 + x_3 = 4 \quad \text{(Equation 5)} \] \[ y_1 + y_3 = 4 \quad \text{(Equation 6)} \] ### Step 2: Solve the System of Equations Now, we have a system of equations to solve for \( x_1, x_2, x_3, y_1, y_2, y_3 \). **From Equations 1, 3, and 5:** 1. From Equation 1: \( x_1 + x_2 = 8 \) 2. From Equation 3: \( x_2 + x_3 = 6 \) 3. From Equation 5: \( x_1 + x_3 = 4 \) We can solve these equations step by step: - From Equation 1, express \( x_2 \): \[ x_2 = 8 - x_1 \quad \text{(Substituting into Equation 3)} \] \[ (8 - x_1) + x_3 = 6 \implies x_3 = 6 - 8 + x_1 = x_1 - 2 \quad \text{(Substituting into Equation 5)} \] \[ x_1 + (x_1 - 2) = 4 \implies 2x_1 - 2 = 4 \implies 2x_1 = 6 \implies x_1 = 3 \] Now substituting \( x_1 = 3 \) back: \[ x_2 = 8 - 3 = 5 \] \[ x_3 = 3 - 2 = 1 \] **Now for the y-coordinates using Equations 2, 4, and 6:** 1. From Equation 2: \( y_1 + y_2 = 4 \) 2. From Equation 4: \( y_2 + y_3 = 6 \) 3. From Equation 6: \( y_1 + y_3 = 4 \) Following the same steps: - From Equation 2, express \( y_2 \): \[ y_2 = 4 - y_1 \quad \text{(Substituting into Equation 4)} \] \[ (4 - y_1) + y_3 = 6 \implies y_3 = 6 - 4 + y_1 = y_1 + 2 \quad \text{(Substituting into Equation 6)} \] \[ y_1 + (y_1 + 2) = 4 \implies 2y_1 + 2 = 4 \implies 2y_1 = 2 \implies y_1 = 1 \] Now substituting \( y_1 = 1 \) back: \[ y_2 = 4 - 1 = 3 \] \[ y_3 = 1 + 2 = 3 \] ### Step 3: Calculate the Centroid The coordinates of the vertices are: - \( A(3, 1) \) - \( B(5, 3) \) - \( C(1, 3) \) The formula for the centroid \( G \) of a triangle is given by: \[ G\left(\frac{x_1 + x_2 + x_3}{3}, \frac{y_1 + y_2 + y_3}{3}\right) \] Substituting the values: \[ G\left(\frac{3 + 5 + 1}{3}, \frac{1 + 3 + 3}{3}\right) = G\left(\frac{9}{3}, \frac{7}{3}\right) = G(3, \frac{7}{3}) \] ### Final Answer The coordinates of the centroid are \( (3, \frac{7}{3}) \). ---
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