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Finding the Fourth Proportional to 186.90, 280.20 and 78.66

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Solution

The fourth proportional to 186.90, 280.20 and 78.66 is: 117.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    186.90 : 280.20 = 78.66 : x
  2. Step 2: Convert to fraction form
    186.90/280.20 = 78.66/x
  3. Step 3: Cross multiply
    186.90x = 280.20 × 78.66
  4. Step 4: Simplify right side
    186.90x = 22,040.53
  5. Step 5: Solve for x
    x = 22,040.53/186.90
  6. Step 6: Final answer
    x = 117.93

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.