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Finding the Fourth Proportional to 278.21, 417.27 and 85.84

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Solution

The fourth proportional to 278.21, 417.27 and 85.84 is: 128.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    278.21 : 417.27 = 85.84 : x
  2. Step 2: Convert to fraction form
    278.21/417.27 = 85.84/x
  3. Step 3: Cross multiply
    278.21x = 417.27 × 85.84
  4. Step 4: Simplify right side
    278.21x = 35,816.37
  5. Step 5: Solve for x
    x = 35,816.37/278.21
  6. Step 6: Final answer
    x = 128.74

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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.