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Finding the Fourth Proportional to 285.11, 427.79 and 138.99

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Solution

The fourth proportional to 285.11, 427.79 and 138.99 is: 208.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.11 : 427.79 = 138.99 : x
  2. Step 2: Convert to fraction form
    285.11/427.79 = 138.99/x
  3. Step 3: Cross multiply
    285.11x = 427.79 × 138.99
  4. Step 4: Simplify right side
    285.11x = 59,458.89
  5. Step 5: Solve for x
    x = 59,458.89/285.11
  6. Step 6: Final answer
    x = 208.55

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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.