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Finding the Fourth Proportional to 31.05, 42.75 and 28.53

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Solution

The fourth proportional to 31.05, 42.75 and 28.53 is: 39.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.05 : 42.75 = 28.53 : x
  2. Step 2: Convert to fraction form
    31.05/42.75 = 28.53/x
  3. Step 3: Cross multiply
    31.05x = 42.75 × 28.53
  4. Step 4: Simplify right side
    31.05x = 1,219.66
  5. Step 5: Solve for x
    x = 1,219.66/31.05
  6. Step 6: Final answer
    x = 39.28

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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.