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Finding the Fourth Proportional to 280.98, 421.47 and 85.98

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Solution

The fourth proportional to 280.98, 421.47 and 85.98 is: 128.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.98 : 421.47 = 85.98 : x
  2. Step 2: Convert to fraction form
    280.98/421.47 = 85.98/x
  3. Step 3: Cross multiply
    280.98x = 421.47 × 85.98
  4. Step 4: Simplify right side
    280.98x = 36,237.99
  5. Step 5: Solve for x
    x = 36,237.99/280.98
  6. Step 6: Final answer
    x = 128.97

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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.