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Finding the Fourth Proportional to 151.68, 209.30 and 85.28

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Solution

The fourth proportional to 151.68, 209.30 and 85.28 is: 117.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    151.68 : 209.30 = 85.28 : x
  2. Step 2: Convert to fraction form
    151.68/209.30 = 85.28/x
  3. Step 3: Cross multiply
    151.68x = 209.30 × 85.28
  4. Step 4: Simplify right side
    151.68x = 17,849.87
  5. Step 5: Solve for x
    x = 17,849.87/151.68
  6. Step 6: Final answer
    x = 117.68

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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.