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Finding the Fourth Proportional to 186.78, 257.71 and 121.33

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Solution

The fourth proportional to 186.78, 257.71 and 121.33 is: 167.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    186.78 : 257.71 = 121.33 : x
  2. Step 2: Convert to fraction form
    186.78/257.71 = 121.33/x
  3. Step 3: Cross multiply
    186.78x = 257.71 × 121.33
  4. Step 4: Simplify right side
    186.78x = 31,267.95
  5. Step 5: Solve for x
    x = 31,267.95/186.78
  6. Step 6: Final answer
    x = 167.41

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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.