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Finding the Fourth Proportional to 29.90, 41.20 and 21.70

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Solution

The fourth proportional to 29.90, 41.20 and 21.70 is: 29.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    29.90 : 41.20 = 21.70 : x
  2. Step 2: Convert to fraction form
    29.90/41.20 = 21.70/x
  3. Step 3: Cross multiply
    29.90x = 41.20 × 21.70
  4. Step 4: Simplify right side
    29.90x = 894.04
  5. Step 5: Solve for x
    x = 894.04/29.90
  6. Step 6: Final answer
    x = 29.90

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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.