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Finding the Fourth Proportional to 91.72, 137.82 and 77.64

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Solution

The fourth proportional to 91.72, 137.82 and 77.64 is: 116.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.72 : 137.82 = 77.64 : x
  2. Step 2: Convert to fraction form
    91.72/137.82 = 77.64/x
  3. Step 3: Cross multiply
    91.72x = 137.82 × 77.64
  4. Step 4: Simplify right side
    91.72x = 10,700.34
  5. Step 5: Solve for x
    x = 10,700.34/91.72
  6. Step 6: Final answer
    x = 116.66

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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.