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Finding the Fourth Proportional to 761.81, 1,139.97 and 486.61

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Solution

The fourth proportional to 761.81, 1,139.97 and 486.61 is: 728.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    761.81 : 1,139.97 = 486.61 : x
  2. Step 2: Convert to fraction form
    761.81/1,139.97 = 486.61/x
  3. Step 3: Cross multiply
    761.81x = 1,139.97 × 486.61
  4. Step 4: Simplify right side
    761.81x = 554,719.78
  5. Step 5: Solve for x
    x = 554,719.78/761.81
  6. Step 6: Final answer
    x = 728.17

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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.