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Finding the Fourth Proportional to 15.53, 21.40 and 11.15

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Solution

The fourth proportional to 15.53, 21.40 and 11.15 is: 15.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.53 : 21.40 = 11.15 : x
  2. Step 2: Convert to fraction form
    15.53/21.40 = 11.15/x
  3. Step 3: Cross multiply
    15.53x = 21.40 × 11.15
  4. Step 4: Simplify right side
    15.53x = 238.68
  5. Step 5: Solve for x
    x = 238.68/15.53
  6. Step 6: Final answer
    x = 15.37

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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.