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Finding the Fourth Proportional to 879.60, 1,311.42 and 856.80

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Solution

The fourth proportional to 879.60, 1,311.42 and 856.80 is: 1,277.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    879.60 : 1,311.42 = 856.80 : x
  2. Step 2: Convert to fraction form
    879.60/1,311.42 = 856.80/x
  3. Step 3: Cross multiply
    879.60x = 1,311.42 × 856.80
  4. Step 4: Simplify right side
    879.60x = 1,123,624.66
  5. Step 5: Solve for x
    x = 1,123,624.66/879.60
  6. Step 6: Final answer
    x = 1,277.43

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.