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Finding the Fourth Proportional to 31.08, 42.85 and 25.60

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Solution

The fourth proportional to 31.08, 42.85 and 25.60 is: 35.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.08 : 42.85 = 25.60 : x
  2. Step 2: Convert to fraction form
    31.08/42.85 = 25.60/x
  3. Step 3: Cross multiply
    31.08x = 42.85 × 25.60
  4. Step 4: Simplify right side
    31.08x = 1,096.96
  5. Step 5: Solve for x
    x = 1,096.96/31.08
  6. Step 6: Final answer
    x = 35.29

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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.