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Finding the Fourth Proportional to 28.98, 40.00 and 15.87

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Solution

The fourth proportional to 28.98, 40.00 and 15.87 is: 21.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.98 : 40.00 = 15.87 : x
  2. Step 2: Convert to fraction form
    28.98/40.00 = 15.87/x
  3. Step 3: Cross multiply
    28.98x = 40.00 × 15.87
  4. Step 4: Simplify right side
    28.98x = 634.75
  5. Step 5: Solve for x
    x = 634.75/28.98
  6. Step 6: Final answer
    x = 21.90

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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.