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Finding the Fourth Proportional to 685.94, 946.68 and 391.28

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Solution

The fourth proportional to 685.94, 946.68 and 391.28 is: 540.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.94 : 946.68 = 391.28 : x
  2. Step 2: Convert to fraction form
    685.94/946.68 = 391.28/x
  3. Step 3: Cross multiply
    685.94x = 946.68 × 391.28
  4. Step 4: Simplify right side
    685.94x = 370,416.95
  5. Step 5: Solve for x
    x = 370,416.95/685.94
  6. Step 6: Final answer
    x = 540.01

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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.