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Finding the Fourth Proportional to 30.96, 42.72 and 25.20

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Solution

The fourth proportional to 30.96, 42.72 and 25.20 is: 34.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.96 : 42.72 = 25.20 : x
  2. Step 2: Convert to fraction form
    30.96/42.72 = 25.20/x
  3. Step 3: Cross multiply
    30.96x = 42.72 × 25.20
  4. Step 4: Simplify right side
    30.96x = 1,076.54
  5. Step 5: Solve for x
    x = 1,076.54/30.96
  6. Step 6: Final answer
    x = 34.77

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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.