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Finding the Fourth Proportional to 279.40, 418.20 and 257.80

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Solution

The fourth proportional to 279.40, 418.20 and 257.80 is: 385.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    279.40 : 418.20 = 257.80 : x
  2. Step 2: Convert to fraction form
    279.40/418.20 = 257.80/x
  3. Step 3: Cross multiply
    279.40x = 418.20 × 257.80
  4. Step 4: Simplify right side
    279.40x = 107,811.96
  5. Step 5: Solve for x
    x = 107,811.96/279.40
  6. Step 6: Final answer
    x = 385.87

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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.