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Finding the Fourth Proportional to 686.15, 946.92 and 391.48

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Solution

The fourth proportional to 686.15, 946.92 and 391.48 is: 540.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.15 : 946.92 = 391.48 : x
  2. Step 2: Convert to fraction form
    686.15/946.92 = 391.48/x
  3. Step 3: Cross multiply
    686.15x = 946.92 × 391.48
  4. Step 4: Simplify right side
    686.15x = 370,699.34
  5. Step 5: Solve for x
    x = 370,699.34/686.15
  6. Step 6: Final answer
    x = 540.26

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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.