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Finding the Fourth Proportional to 279.59, 419.40 and 87.21

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Solution

The fourth proportional to 279.59, 419.40 and 87.21 is: 130.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    279.59 : 419.40 = 87.21 : x
  2. Step 2: Convert to fraction form
    279.59/419.40 = 87.21/x
  3. Step 3: Cross multiply
    279.59x = 419.40 × 87.21
  4. Step 4: Simplify right side
    279.59x = 36,575.87
  5. Step 5: Solve for x
    x = 36,575.87/279.59
  6. Step 6: Final answer
    x = 130.82

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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.