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Finding the Fourth Proportional to 28.61, 42.99 and 15.78

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Solution

The fourth proportional to 28.61, 42.99 and 15.78 is: 23.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.61 : 42.99 = 15.78 : x
  2. Step 2: Convert to fraction form
    28.61/42.99 = 15.78/x
  3. Step 3: Cross multiply
    28.61x = 42.99 × 15.78
  4. Step 4: Simplify right side
    28.61x = 678.38
  5. Step 5: Solve for x
    x = 678.38/28.61
  6. Step 6: Final answer
    x = 23.72

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.