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Finding the Fourth Proportional to 717.86, 991 and 486.20

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Solution

The fourth proportional to 717.86, 991 and 486.20 is: 671.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    717.86 : 991 = 486.20 : x
  2. Step 2: Convert to fraction form
    717.86/991 = 486.20/x
  3. Step 3: Cross multiply
    717.86x = 991 × 486.20
  4. Step 4: Simplify right side
    717.86x = 481,824.20
  5. Step 5: Solve for x
    x = 481,824.20/717.86
  6. Step 6: Final answer
    x = 671.20

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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.