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Finding the Fourth Proportional to 921.16, 1,380.30 and 487.72

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Solution

The fourth proportional to 921.16, 1,380.30 and 487.72 is: 730.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.16 : 1,380.30 = 487.72 : x
  2. Step 2: Convert to fraction form
    921.16/1,380.30 = 487.72/x
  3. Step 3: Cross multiply
    921.16x = 1,380.30 × 487.72
  4. Step 4: Simplify right side
    921.16x = 673,199.92
  5. Step 5: Solve for x
    x = 673,199.92/921.16
  6. Step 6: Final answer
    x = 730.82

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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.