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Finding the Fourth Proportional to 128.77, 193.20 and 77.51

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Solution

The fourth proportional to 128.77, 193.20 and 77.51 is: 116.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.77 : 193.20 = 77.51 : x
  2. Step 2: Convert to fraction form
    128.77/193.20 = 77.51/x
  3. Step 3: Cross multiply
    128.77x = 193.20 × 77.51
  4. Step 4: Simplify right side
    128.77x = 14,974.93
  5. Step 5: Solve for x
    x = 14,974.93/128.77
  6. Step 6: Final answer
    x = 116.29

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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.