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Finding the Fourth Proportional to 86.78, 130.16 and 25.90

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Solution

The fourth proportional to 86.78, 130.16 and 25.90 is: 38.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.78 : 130.16 = 25.90 : x
  2. Step 2: Convert to fraction form
    86.78/130.16 = 25.90/x
  3. Step 3: Cross multiply
    86.78x = 130.16 × 25.90
  4. Step 4: Simplify right side
    86.78x = 3,370.88
  5. Step 5: Solve for x
    x = 3,370.88/86.78
  6. Step 6: Final answer
    x = 38.84

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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.