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Finding the Fourth Proportional to 891.79, 1,230.68 and 518.78

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Solution

The fourth proportional to 891.79, 1,230.68 and 518.78 is: 715.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    891.79 : 1,230.68 = 518.78 : x
  2. Step 2: Convert to fraction form
    891.79/1,230.68 = 518.78/x
  3. Step 3: Cross multiply
    891.79x = 1,230.68 × 518.78
  4. Step 4: Simplify right side
    891.79x = 638,456.54
  5. Step 5: Solve for x
    x = 638,456.54/891.79
  6. Step 6: Final answer
    x = 715.93

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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.