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Finding the Fourth Proportional to 686.33, 946.90 and 391.39

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Solution

The fourth proportional to 686.33, 946.90 and 391.39 is: 539.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.33 : 946.90 = 391.39 : x
  2. Step 2: Convert to fraction form
    686.33/946.90 = 391.39/x
  3. Step 3: Cross multiply
    686.33x = 946.90 × 391.39
  4. Step 4: Simplify right side
    686.33x = 370,607.19
  5. Step 5: Solve for x
    x = 370,607.19/686.33
  6. Step 6: Final answer
    x = 539.98

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1.5x scale

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.