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Finding the Fourth Proportional to 279.40, 385.55 and 155.05

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Solution

The fourth proportional to 279.40, 385.55 and 155.05 is: 213.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    279.40 : 385.55 = 155.05 : x
  2. Step 2: Convert to fraction form
    279.40/385.55 = 155.05/x
  3. Step 3: Cross multiply
    279.40x = 385.55 × 155.05
  4. Step 4: Simplify right side
    279.40x = 59,778.18
  5. Step 5: Solve for x
    x = 59,778.18/279.40
  6. Step 6: Final answer
    x = 213.96

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.