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Finding the Fourth Proportional to 151.78, 209.47 and 86.29

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Solution

The fourth proportional to 151.78, 209.47 and 86.29 is: 119.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    151.78 : 209.47 = 86.29 : x
  2. Step 2: Convert to fraction form
    151.78/209.47 = 86.29/x
  3. Step 3: Cross multiply
    151.78x = 209.47 × 86.29
  4. Step 4: Simplify right side
    151.78x = 18,075.17
  5. Step 5: Solve for x
    x = 18,075.17/151.78
  6. Step 6: Final answer
    x = 119.09

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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.