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Finding the Fourth Proportional to 30.72, 42.16 and 29.90

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Solution

The fourth proportional to 30.72, 42.16 and 29.90 is: 41.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.72 : 42.16 = 29.90 : x
  2. Step 2: Convert to fraction form
    30.72/42.16 = 29.90/x
  3. Step 3: Cross multiply
    30.72x = 42.16 × 29.90
  4. Step 4: Simplify right side
    30.72x = 1,260.58
  5. Step 5: Solve for x
    x = 1,260.58/30.72
  6. Step 6: Final answer
    x = 41.03

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.