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Finding the Fourth Proportional to 758.66, 1,139.79 and 485.42

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Solution

The fourth proportional to 758.66, 1,139.79 and 485.42 is: 729.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    758.66 : 1,139.79 = 485.42 : x
  2. Step 2: Convert to fraction form
    758.66/1,139.79 = 485.42/x
  3. Step 3: Cross multiply
    758.66x = 1,139.79 × 485.42
  4. Step 4: Simplify right side
    758.66x = 553,276.86
  5. Step 5: Solve for x
    x = 553,276.86/758.66
  6. Step 6: Final answer
    x = 729.28

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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.