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Finding the Fourth Proportional to 91.15, 136.68 and 80.35

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Solution

The fourth proportional to 91.15, 136.68 and 80.35 is: 120.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.15 : 136.68 = 80.35 : x
  2. Step 2: Convert to fraction form
    91.15/136.68 = 80.35/x
  3. Step 3: Cross multiply
    91.15x = 136.68 × 80.35
  4. Step 4: Simplify right side
    91.15x = 10,981.49
  5. Step 5: Solve for x
    x = 10,981.49/91.15
  6. Step 6: Final answer
    x = 120.47

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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.