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Finding the Fourth Proportional to 21.87, 30.07 and 21.23

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Solution

The fourth proportional to 21.87, 30.07 and 21.23 is: 29.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.87 : 30.07 = 21.23 : x
  2. Step 2: Convert to fraction form
    21.87/30.07 = 21.23/x
  3. Step 3: Cross multiply
    21.87x = 30.07 × 21.23
  4. Step 4: Simplify right side
    21.87x = 638.39
  5. Step 5: Solve for x
    x = 638.39/21.87
  6. Step 6: Final answer
    x = 29.19

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.