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Finding the Fourth Proportional to 665.46, 991.17 and 661.86

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Solution

The fourth proportional to 665.46, 991.17 and 661.86 is: 985.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.46 : 991.17 = 661.86 : x
  2. Step 2: Convert to fraction form
    665.46/991.17 = 661.86/x
  3. Step 3: Cross multiply
    665.46x = 991.17 × 661.86
  4. Step 4: Simplify right side
    665.46x = 656,015.78
  5. Step 5: Solve for x
    x = 656,015.78/665.46
  6. Step 6: Final answer
    x = 985.81

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.