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Finding the Fourth Proportional to 760.20, 1,139.52 and 430.80

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Solution

The fourth proportional to 760.20, 1,139.52 and 430.80 is: 645.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    760.20 : 1,139.52 = 430.80 : x
  2. Step 2: Convert to fraction form
    760.20/1,139.52 = 430.80/x
  3. Step 3: Cross multiply
    760.20x = 1,139.52 × 430.80
  4. Step 4: Simplify right side
    760.20x = 490,905.22
  5. Step 5: Solve for x
    x = 490,905.22/760.20
  6. Step 6: Final answer
    x = 645.76

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.