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Finding the Fourth Proportional to 878.60, 1,212.50 and 505.70

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Solution

The fourth proportional to 878.60, 1,212.50 and 505.70 is: 697.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.60 : 1,212.50 = 505.70 : x
  2. Step 2: Convert to fraction form
    878.60/1,212.50 = 505.70/x
  3. Step 3: Cross multiply
    878.60x = 1,212.50 × 505.70
  4. Step 4: Simplify right side
    878.60x = 613,156.45
  5. Step 5: Solve for x
    x = 613,156.45/878.60
  6. Step 6: Final answer
    x = 697.88

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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.