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Finding the Fourth Proportional to 92.80, 139.29 and 77.68

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Solution

The fourth proportional to 92.80, 139.29 and 77.68 is: 116.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    92.80 : 139.29 = 77.68 : x
  2. Step 2: Convert to fraction form
    92.80/139.29 = 77.68/x
  3. Step 3: Cross multiply
    92.80x = 139.29 × 77.68
  4. Step 4: Simplify right side
    92.80x = 10,820.05
  5. Step 5: Solve for x
    x = 10,820.05/92.80
  6. Step 6: Final answer
    x = 116.60

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.