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Finding the Fourth Proportional to 30.64, 42.21 and 28.75

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Solution

The fourth proportional to 30.64, 42.21 and 28.75 is: 39.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.64 : 42.21 = 28.75 : x
  2. Step 2: Convert to fraction form
    30.64/42.21 = 28.75/x
  3. Step 3: Cross multiply
    30.64x = 42.21 × 28.75
  4. Step 4: Simplify right side
    30.64x = 1,213.54
  5. Step 5: Solve for x
    x = 1,213.54/30.64
  6. Step 6: Final answer
    x = 39.61

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Find fourth proportional to 15.32, 21.11 and 14.38
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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.