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Finding the Fourth Proportional to 21.70, 29.93 and 18.78

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Solution

The fourth proportional to 21.70, 29.93 and 18.78 is: 25.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.70 : 29.93 = 18.78 : x
  2. Step 2: Convert to fraction form
    21.70/29.93 = 18.78/x
  3. Step 3: Cross multiply
    21.70x = 29.93 × 18.78
  4. Step 4: Simplify right side
    21.70x = 561.94
  5. Step 5: Solve for x
    x = 561.94/21.70
  6. Step 6: Final answer
    x = 25.90

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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.