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Finding the Fourth Proportional to 280.78, 420.94 and 126.59

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Solution

The fourth proportional to 280.78, 420.94 and 126.59 is: 189.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.78 : 420.94 = 126.59 : x
  2. Step 2: Convert to fraction form
    280.78/420.94 = 126.59/x
  3. Step 3: Cross multiply
    280.78x = 420.94 × 126.59
  4. Step 4: Simplify right side
    280.78x = 53,284.85
  5. Step 5: Solve for x
    x = 53,284.85/280.78
  6. Step 6: Final answer
    x = 189.78

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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.