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Finding the Fourth Proportional to 279.26, 418.90 and 86.90

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Solution

The fourth proportional to 279.26, 418.90 and 86.90 is: 130.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    279.26 : 418.90 = 86.90 : x
  2. Step 2: Convert to fraction form
    279.26/418.90 = 86.90/x
  3. Step 3: Cross multiply
    279.26x = 418.90 × 86.90
  4. Step 4: Simplify right side
    279.26x = 36,402.41
  5. Step 5: Solve for x
    x = 36,402.41/279.26
  6. Step 6: Final answer
    x = 130.35

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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.