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Finding the Fourth Proportional to 91.86, 137.86 and 43.78

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Solution

The fourth proportional to 91.86, 137.86 and 43.78 is: 65.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.86 : 137.86 = 43.78 : x
  2. Step 2: Convert to fraction form
    91.86/137.86 = 43.78/x
  3. Step 3: Cross multiply
    91.86x = 137.86 × 43.78
  4. Step 4: Simplify right side
    91.86x = 6,035.51
  5. Step 5: Solve for x
    x = 6,035.51/91.86
  6. Step 6: Final answer
    x = 65.70

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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.