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Finding the Fourth Proportional to 30.47, 42.05 and 21.25

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Solution

The fourth proportional to 30.47, 42.05 and 21.25 is: 29.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.47 : 42.05 = 21.25 : x
  2. Step 2: Convert to fraction form
    30.47/42.05 = 21.25/x
  3. Step 3: Cross multiply
    30.47x = 42.05 × 21.25
  4. Step 4: Simplify right side
    30.47x = 893.35
  5. Step 5: Solve for x
    x = 893.35/30.47
  6. Step 6: Final answer
    x = 29.32

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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.