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Finding the Fourth Proportional to 878.52, 1,212.16 and 642.56

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Solution

The fourth proportional to 878.52, 1,212.16 and 642.56 is: 886.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.52 : 1,212.16 = 642.56 : x
  2. Step 2: Convert to fraction form
    878.52/1,212.16 = 642.56/x
  3. Step 3: Cross multiply
    878.52x = 1,212.16 × 642.56
  4. Step 4: Simplify right side
    878.52x = 778,885.53
  5. Step 5: Solve for x
    x = 778,885.53/878.52
  6. Step 6: Final answer
    x = 886.59

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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.