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Finding the Fourth Proportional to 30.55, 42.09 and 21.33

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Solution

The fourth proportional to 30.55, 42.09 and 21.33 is: 29.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.55 : 42.09 = 21.33 : x
  2. Step 2: Convert to fraction form
    30.55/42.09 = 21.33/x
  3. Step 3: Cross multiply
    30.55x = 42.09 × 21.33
  4. Step 4: Simplify right side
    30.55x = 897.46
  5. Step 5: Solve for x
    x = 897.46/30.55
  6. Step 6: Final answer
    x = 29.38

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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.