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Finding the Fourth Proportional to 128.88, 177.85 and 70.66

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Solution

The fourth proportional to 128.88, 177.85 and 70.66 is: 97.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.88 : 177.85 = 70.66 : x
  2. Step 2: Convert to fraction form
    128.88/177.85 = 70.66/x
  3. Step 3: Cross multiply
    128.88x = 177.85 × 70.66
  4. Step 4: Simplify right side
    128.88x = 12,566.70
  5. Step 5: Solve for x
    x = 12,566.70/128.88
  6. Step 6: Final answer
    x = 97.51

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.