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Finding the Fourth Proportional to 278.64, 418.02 and 86.25

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Solution

The fourth proportional to 278.64, 418.02 and 86.25 is: 129.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    278.64 : 418.02 = 86.25 : x
  2. Step 2: Convert to fraction form
    278.64/418.02 = 86.25/x
  3. Step 3: Cross multiply
    278.64x = 418.02 × 86.25
  4. Step 4: Simplify right side
    278.64x = 36,054.23
  5. Step 5: Solve for x
    x = 36,054.23/278.64
  6. Step 6: Final answer
    x = 129.39

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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.