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Finding the Fourth Proportional to 909.89, 1,256.07 and 685.91

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Solution

The fourth proportional to 909.89, 1,256.07 and 685.91 is: 946.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    909.89 : 1,256.07 = 685.91 : x
  2. Step 2: Convert to fraction form
    909.89/1,256.07 = 685.91/x
  3. Step 3: Cross multiply
    909.89x = 1,256.07 × 685.91
  4. Step 4: Simplify right side
    909.89x = 861,551.03
  5. Step 5: Solve for x
    x = 861,551.03/909.89
  6. Step 6: Final answer
    x = 946.88

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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.