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Finding the Fourth Proportional to 661.96, 991.86 and 417.70

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Solution

The fourth proportional to 661.96, 991.86 and 417.70 is: 625.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.96 : 991.86 = 417.70 : x
  2. Step 2: Convert to fraction form
    661.96/991.86 = 417.70/x
  3. Step 3: Cross multiply
    661.96x = 991.86 × 417.70
  4. Step 4: Simplify right side
    661.96x = 414,299.92
  5. Step 5: Solve for x
    x = 414,299.92/661.96
  6. Step 6: Final answer
    x = 625.87

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.