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Finding the Fourth Proportional to 91.65, 136.73 and 78.66

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Solution

The fourth proportional to 91.65, 136.73 and 78.66 is: 117.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.65 : 136.73 = 78.66 : x
  2. Step 2: Convert to fraction form
    91.65/136.73 = 78.66/x
  3. Step 3: Cross multiply
    91.65x = 136.73 × 78.66
  4. Step 4: Simplify right side
    91.65x = 10,755.18
  5. Step 5: Solve for x
    x = 10,755.18/91.65
  6. Step 6: Final answer
    x = 117.35

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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.