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Finding the Fourth Proportional to 661.20, 989.46 and 487.46

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Solution

The fourth proportional to 661.20, 989.46 and 487.46 is: 729.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.20 : 989.46 = 487.46 : x
  2. Step 2: Convert to fraction form
    661.20/989.46 = 487.46/x
  3. Step 3: Cross multiply
    661.20x = 989.46 × 487.46
  4. Step 4: Simplify right side
    661.20x = 482,317.22
  5. Step 5: Solve for x
    x = 482,317.22/661.20
  6. Step 6: Final answer
    x = 729.46

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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.