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Finding the Fourth Proportional to 753.20, 1,129.80 and 429.20

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Solution

The fourth proportional to 753.20, 1,129.80 and 429.20 is: 643.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    753.20 : 1,129.80 = 429.20 : x
  2. Step 2: Convert to fraction form
    753.20/1,129.80 = 429.20/x
  3. Step 3: Cross multiply
    753.20x = 1,129.80 × 429.20
  4. Step 4: Simplify right side
    753.20x = 484,910.16
  5. Step 5: Solve for x
    x = 484,910.16/753.20
  6. Step 6: Final answer
    x = 643.80

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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.