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Finding the Fourth Proportional to 278.46, 417.78 and 105.21

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Solution

The fourth proportional to 278.46, 417.78 and 105.21 is: 157.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    278.46 : 417.78 = 105.21 : x
  2. Step 2: Convert to fraction form
    278.46/417.78 = 105.21/x
  3. Step 3: Cross multiply
    278.46x = 417.78 × 105.21
  4. Step 4: Simplify right side
    278.46x = 43,954.63
  5. Step 5: Solve for x
    x = 43,954.63/278.46
  6. Step 6: Final answer
    x = 157.85

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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.