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Finding the Fourth Proportional to 91.42, 136.39 and 77.74

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Solution

The fourth proportional to 91.42, 136.39 and 77.74 is: 115.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.42 : 136.39 = 77.74 : x
  2. Step 2: Convert to fraction form
    91.42/136.39 = 77.74/x
  3. Step 3: Cross multiply
    91.42x = 136.39 × 77.74
  4. Step 4: Simplify right side
    91.42x = 10,602.96
  5. Step 5: Solve for x
    x = 10,602.96/91.42
  6. Step 6: Final answer
    x = 115.98

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.