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Finding the Fourth Proportional to 186.90, 280.08 and 78.57

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Solution

The fourth proportional to 186.90, 280.08 and 78.57 is: 117.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    186.90 : 280.08 = 78.57 : x
  2. Step 2: Convert to fraction form
    186.90/280.08 = 78.57/x
  3. Step 3: Cross multiply
    186.90x = 280.08 × 78.57
  4. Step 4: Simplify right side
    186.90x = 22,005.89
  5. Step 5: Solve for x
    x = 22,005.89/186.90
  6. Step 6: Final answer
    x = 117.74

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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.