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Finding the Fourth Proportional to 921.87, 1,272.32 and 518.15

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Solution

The fourth proportional to 921.87, 1,272.32 and 518.15 is: 715.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.87 : 1,272.32 = 518.15 : x
  2. Step 2: Convert to fraction form
    921.87/1,272.32 = 518.15/x
  3. Step 3: Cross multiply
    921.87x = 1,272.32 × 518.15
  4. Step 4: Simplify right side
    921.87x = 659,252.61
  5. Step 5: Solve for x
    x = 659,252.61/921.87
  6. Step 6: Final answer
    x = 715.13

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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.