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Finding the Fourth Proportional to 878.80, 1,212.50 and 505.79

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Solution

The fourth proportional to 878.80, 1,212.50 and 505.79 is: 697.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.80 : 1,212.50 = 505.79 : x
  2. Step 2: Convert to fraction form
    878.80/1,212.50 = 505.79/x
  3. Step 3: Cross multiply
    878.80x = 1,212.50 × 505.79
  4. Step 4: Simplify right side
    878.80x = 613,270.38
  5. Step 5: Solve for x
    x = 613,270.38/878.80
  6. Step 6: Final answer
    x = 697.85

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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.