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Finding the Fourth Proportional to 30.80, 42.58 and 28.41

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Solution

The fourth proportional to 30.80, 42.58 and 28.41 is: 39.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.80 : 42.58 = 28.41 : x
  2. Step 2: Convert to fraction form
    30.80/42.58 = 28.41/x
  3. Step 3: Cross multiply
    30.80x = 42.58 × 28.41
  4. Step 4: Simplify right side
    30.80x = 1,209.70
  5. Step 5: Solve for x
    x = 1,209.70/30.80
  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.