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Finding the Fourth Proportional to 493.78, 681.42 and 307.21

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Solution

The fourth proportional to 493.78, 681.42 and 307.21 is: 423.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    493.78 : 681.42 = 307.21 : x
  2. Step 2: Convert to fraction form
    493.78/681.42 = 307.21/x
  3. Step 3: Cross multiply
    493.78x = 681.42 × 307.21
  4. Step 4: Simplify right side
    493.78x = 209,339.04
  5. Step 5: Solve for x
    x = 209,339.04/493.78
  6. Step 6: Final answer
    x = 423.95

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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.