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Finding the Fourth Proportional to 687.92, 1,036.32 and 518

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Solution

The fourth proportional to 687.92, 1,036.32 and 518 is: 780.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.92 : 1,036.32 = 518 : x
  2. Step 2: Convert to fraction form
    687.92/1,036.32 = 518/x
  3. Step 3: Cross multiply
    687.92x = 1,036.32 × 518
  4. Step 4: Simplify right side
    687.92x = 536,813.76
  5. Step 5: Solve for x
    x = 536,813.76/687.92
  6. Step 6: Final answer
    x = 780.34

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.