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Finding the Fourth Proportional to 128.79, 193.89 and 88.47

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Solution

The fourth proportional to 128.79, 193.89 and 88.47 is: 133.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.79 : 193.89 = 88.47 : x
  2. Step 2: Convert to fraction form
    128.79/193.89 = 88.47/x
  3. Step 3: Cross multiply
    128.79x = 193.89 × 88.47
  4. Step 4: Simplify right side
    128.79x = 17,153.01
  5. Step 5: Solve for x
    x = 17,153.01/128.79
  6. Step 6: Final answer
    x = 133.19

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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.