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Finding the Fourth Proportional to 77.09, 115.13 and 61.90

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Solution

The fourth proportional to 77.09, 115.13 and 61.90 is: 92.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.09 : 115.13 = 61.90 : x
  2. Step 2: Convert to fraction form
    77.09/115.13 = 61.90/x
  3. Step 3: Cross multiply
    77.09x = 115.13 × 61.90
  4. Step 4: Simplify right side
    77.09x = 7,126.41
  5. Step 5: Solve for x
    x = 7,126.41/77.09
  6. Step 6: Final answer
    x = 92.45

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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.