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Finding the Fourth Proportional to 660.85, 991.61 and 429.68

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Solution

The fourth proportional to 660.85, 991.61 and 429.68 is: 644.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.85 : 991.61 = 429.68 : x
  2. Step 2: Convert to fraction form
    660.85/991.61 = 429.68/x
  3. Step 3: Cross multiply
    660.85x = 991.61 × 429.68
  4. Step 4: Simplify right side
    660.85x = 426,074.98
  5. Step 5: Solve for x
    x = 426,074.98/660.85
  6. Step 6: Final answer
    x = 644.74

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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.