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Finding the Fourth Proportional to 661.92, 912.96 and 487.20

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Solution

The fourth proportional to 661.92, 912.96 and 487.20 is: 671.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.92 : 912.96 = 487.20 : x
  2. Step 2: Convert to fraction form
    661.92/912.96 = 487.20/x
  3. Step 3: Cross multiply
    661.92x = 912.96 × 487.20
  4. Step 4: Simplify right side
    661.92x = 444,794.11
  5. Step 5: Solve for x
    x = 444,794.11/661.92
  6. Step 6: Final answer
    x = 671.98

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.