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Finding the Fourth Proportional to 518.75, 781.70 and 429.45

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Solution

The fourth proportional to 518.75, 781.70 and 429.45 is: 647.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    518.75 : 781.70 = 429.45 : x
  2. Step 2: Convert to fraction form
    518.75/781.70 = 429.45/x
  3. Step 3: Cross multiply
    518.75x = 781.70 × 429.45
  4. Step 4: Simplify right side
    518.75x = 335,698.92
  5. Step 5: Solve for x
    x = 335,698.92/518.75
  6. Step 6: Final answer
    x = 647.14

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.