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Finding the Fourth Proportional to 551.78, 761.49 and 315.72

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Solution

The fourth proportional to 551.78, 761.49 and 315.72 is: 435.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    551.78 : 761.49 = 315.72 : x
  2. Step 2: Convert to fraction form
    551.78/761.49 = 315.72/x
  3. Step 3: Cross multiply
    551.78x = 761.49 × 315.72
  4. Step 4: Simplify right side
    551.78x = 240,417.62
  5. Step 5: Solve for x
    x = 240,417.62/551.78
  6. Step 6: Final answer
    x = 435.72

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.