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Finding the Fourth Proportional to 279.20, 418.80 and 259.40

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Solution

The fourth proportional to 279.20, 418.80 and 259.40 is: 389.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    279.20 : 418.80 = 259.40 : x
  2. Step 2: Convert to fraction form
    279.20/418.80 = 259.40/x
  3. Step 3: Cross multiply
    279.20x = 418.80 × 259.40
  4. Step 4: Simplify right side
    279.20x = 108,636.72
  5. Step 5: Solve for x
    x = 108,636.72/279.20
  6. Step 6: Final answer
    x = 389.10

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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.