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Finding the Fourth Proportional to 15.53, 21.45 and 15.05

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Solution

The fourth proportional to 15.53, 21.45 and 15.05 is: 20.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.53 : 21.45 = 15.05 : x
  2. Step 2: Convert to fraction form
    15.53/21.45 = 15.05/x
  3. Step 3: Cross multiply
    15.53x = 21.45 × 15.05
  4. Step 4: Simplify right side
    15.53x = 322.64
  5. Step 5: Solve for x
    x = 322.64/15.53
  6. Step 6: Final answer
    x = 20.78

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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.