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Finding the Fourth Proportional to 21.87, 29.76 and 21.81

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Solution

The fourth proportional to 21.87, 29.76 and 21.81 is: 29.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.87 : 29.76 = 21.81 : x
  2. Step 2: Convert to fraction form
    21.87/29.76 = 21.81/x
  3. Step 3: Cross multiply
    21.87x = 29.76 × 21.81
  4. Step 4: Simplify right side
    21.87x = 649.07
  5. Step 5: Solve for x
    x = 649.07/21.87
  6. Step 6: Final answer
    x = 29.68

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Why These Related Problems?

These problems maintain the same ratio (1.36) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.