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Finding the Fourth Proportional to 91.47, 136.47 and 85.59

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Solution

The fourth proportional to 91.47, 136.47 and 85.59 is: 127.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.47 : 136.47 = 85.59 : x
  2. Step 2: Convert to fraction form
    91.47/136.47 = 85.59/x
  3. Step 3: Cross multiply
    91.47x = 136.47 × 85.59
  4. Step 4: Simplify right side
    91.47x = 11,680.47
  5. Step 5: Solve for x
    x = 11,680.47/91.47
  6. Step 6: Final answer
    x = 127.70

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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.