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Finding the Fourth Proportional to 15.75, 21.74 and 11.15

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Solution

The fourth proportional to 15.75, 21.74 and 11.15 is: 15.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.75 : 21.74 = 11.15 : x
  2. Step 2: Convert to fraction form
    15.75/21.74 = 11.15/x
  3. Step 3: Cross multiply
    15.75x = 21.74 × 11.15
  4. Step 4: Simplify right side
    15.75x = 242.40
  5. Step 5: Solve for x
    x = 242.40/15.75
  6. Step 6: Final answer
    x = 15.39

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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.