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Finding the Fourth Proportional to 136.81, 188.65 and 105.72

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Solution

The fourth proportional to 136.81, 188.65 and 105.72 is: 145.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.81 : 188.65 = 105.72 : x
  2. Step 2: Convert to fraction form
    136.81/188.65 = 105.72/x
  3. Step 3: Cross multiply
    136.81x = 188.65 × 105.72
  4. Step 4: Simplify right side
    136.81x = 19,944.08
  5. Step 5: Solve for x
    x = 19,944.08/136.81
  6. Step 6: Final answer
    x = 145.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.