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Finding the Fourth Proportional to 189.81, 284.86 and 138.47

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Solution

The fourth proportional to 189.81, 284.86 and 138.47 is: 207.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    189.81 : 284.86 = 138.47 : x
  2. Step 2: Convert to fraction form
    189.81/284.86 = 138.47/x
  3. Step 3: Cross multiply
    189.81x = 284.86 × 138.47
  4. Step 4: Simplify right side
    189.81x = 39,444.56
  5. Step 5: Solve for x
    x = 39,444.56/189.81
  6. Step 6: Final answer
    x = 207.82

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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.