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Finding the Fourth Proportional to 151.86, 209.46 and 128.76

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Solution

The fourth proportional to 151.86, 209.46 and 128.76 is: 177.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    151.86 : 209.46 = 128.76 : x
  2. Step 2: Convert to fraction form
    151.86/209.46 = 128.76/x
  3. Step 3: Cross multiply
    151.86x = 209.46 × 128.76
  4. Step 4: Simplify right side
    151.86x = 26,970.07
  5. Step 5: Solve for x
    x = 26,970.07/151.86
  6. Step 6: Final answer
    x = 177.60

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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.