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Finding the Fourth Proportional to 31.28, 43.12 and 25.80

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Solution

The fourth proportional to 31.28, 43.12 and 25.80 is: 35.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.28 : 43.12 = 25.80 : x
  2. Step 2: Convert to fraction form
    31.28/43.12 = 25.80/x
  3. Step 3: Cross multiply
    31.28x = 43.12 × 25.80
  4. Step 4: Simplify right side
    31.28x = 1,112.50
  5. Step 5: Solve for x
    x = 1,112.50/31.28
  6. Step 6: Final answer
    x = 35.57

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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.