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Finding the Fourth Proportional to 91.23, 137.49 and 77.87

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Solution

The fourth proportional to 91.23, 137.49 and 77.87 is: 117.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.23 : 137.49 = 77.87 : x
  2. Step 2: Convert to fraction form
    91.23/137.49 = 77.87/x
  3. Step 3: Cross multiply
    91.23x = 137.49 × 77.87
  4. Step 4: Simplify right side
    91.23x = 10,705.66
  5. Step 5: Solve for x
    x = 10,705.66/91.23
  6. Step 6: Final answer
    x = 117.35

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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.