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Finding the Fourth Proportional to 128.47, 191.76 and 117.65

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Solution

The fourth proportional to 128.47, 191.76 and 117.65 is: 175.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.47 : 191.76 = 117.65 : x
  2. Step 2: Convert to fraction form
    128.47/191.76 = 117.65/x
  3. Step 3: Cross multiply
    128.47x = 191.76 × 117.65
  4. Step 4: Simplify right side
    128.47x = 22,559.61
  5. Step 5: Solve for x
    x = 22,559.61/128.47
  6. Step 6: Final answer
    x = 175.61

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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.