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Finding the Fourth Proportional to 661.45, 989.84 and 487.71

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Solution

The fourth proportional to 661.45, 989.84 and 487.71 is: 729.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.45 : 989.84 = 487.71 : x
  2. Step 2: Convert to fraction form
    661.45/989.84 = 487.71/x
  3. Step 3: Cross multiply
    661.45x = 989.84 × 487.71
  4. Step 4: Simplify right side
    661.45x = 482,747.48
  5. Step 5: Solve for x
    x = 482,747.48/661.45
  6. Step 6: Final answer
    x = 729.83

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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.