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Finding the Fourth Proportional to 186.86, 280.40 and 78.65

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Solution

The fourth proportional to 186.86, 280.40 and 78.65 is: 118.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    186.86 : 280.40 = 78.65 : x
  2. Step 2: Convert to fraction form
    186.86/280.40 = 78.65/x
  3. Step 3: Cross multiply
    186.86x = 280.40 × 78.65
  4. Step 4: Simplify right side
    186.86x = 22,052.33
  5. Step 5: Solve for x
    x = 22,052.33/186.86
  6. Step 6: Final answer
    x = 118.02

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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.