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Finding the Fourth Proportional to 386.71, 532.98 and 311.78

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Solution

The fourth proportional to 386.71, 532.98 and 311.78 is: 429.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.71 : 532.98 = 311.78 : x
  2. Step 2: Convert to fraction form
    386.71/532.98 = 311.78/x
  3. Step 3: Cross multiply
    386.71x = 532.98 × 311.78
  4. Step 4: Simplify right side
    386.71x = 166,173.84
  5. Step 5: Solve for x
    x = 166,173.84/386.71
  6. Step 6: Final answer
    x = 429.71

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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.