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Finding the Fourth Proportional to 280.32, 420.39 and 85.26

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Solution

The fourth proportional to 280.32, 420.39 and 85.26 is: 127.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.32 : 420.39 = 85.26 : x
  2. Step 2: Convert to fraction form
    280.32/420.39 = 85.26/x
  3. Step 3: Cross multiply
    280.32x = 420.39 × 85.26
  4. Step 4: Simplify right side
    280.32x = 35,842.45
  5. Step 5: Solve for x
    x = 35,842.45/280.32
  6. Step 6: Final answer
    x = 127.86

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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.