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Finding the Fourth Proportional to 278.19, 417.36 and 85.82

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Solution

The fourth proportional to 278.19, 417.36 and 85.82 is: 128.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    278.19 : 417.36 = 85.82 : x
  2. Step 2: Convert to fraction form
    278.19/417.36 = 85.82/x
  3. Step 3: Cross multiply
    278.19x = 417.36 × 85.82
  4. Step 4: Simplify right side
    278.19x = 35,817.84
  5. Step 5: Solve for x
    x = 35,817.84/278.19
  6. Step 6: Final answer
    x = 128.75

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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.