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Finding the Fourth Proportional to 278.70, 417.99 and 86.22

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Solution

The fourth proportional to 278.70, 417.99 and 86.22 is: 129.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    278.70 : 417.99 = 86.22 : x
  2. Step 2: Convert to fraction form
    278.70/417.99 = 86.22/x
  3. Step 3: Cross multiply
    278.70x = 417.99 × 86.22
  4. Step 4: Simplify right side
    278.70x = 36,039.10
  5. Step 5: Solve for x
    x = 36,039.10/278.70
  6. Step 6: Final answer
    x = 129.31

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.