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Finding the Fourth Proportional to 91.40, 137.61 and 80.63

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Solution

The fourth proportional to 91.40, 137.61 and 80.63 is: 121.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.40 : 137.61 = 80.63 : x
  2. Step 2: Convert to fraction form
    91.40/137.61 = 80.63/x
  3. Step 3: Cross multiply
    91.40x = 137.61 × 80.63
  4. Step 4: Simplify right side
    91.40x = 11,095.84
  5. Step 5: Solve for x
    x = 11,095.84/91.40
  6. Step 6: Final answer
    x = 121.41

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.