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Finding the Fourth Proportional to 15.42, 21.28 and 8.51

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Solution

The fourth proportional to 15.42, 21.28 and 8.51 is: 11.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.42 : 21.28 = 8.51 : x
  2. Step 2: Convert to fraction form
    15.42/21.28 = 8.51/x
  3. Step 3: Cross multiply
    15.42x = 21.28 × 8.51
  4. Step 4: Simplify right side
    15.42x = 181.16
  5. Step 5: Solve for x
    x = 181.16/15.42
  6. Step 6: Final answer
    x = 11.75

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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.