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Finding the Fourth Proportional to 15.90, 21.92 and 13.17

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Solution

The fourth proportional to 15.90, 21.92 and 13.17 is: 18.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.90 : 21.92 = 13.17 : x
  2. Step 2: Convert to fraction form
    15.90/21.92 = 13.17/x
  3. Step 3: Cross multiply
    15.90x = 21.92 × 13.17
  4. Step 4: Simplify right side
    15.90x = 288.51
  5. Step 5: Solve for x
    x = 288.51/15.90
  6. Step 6: Final answer
    x = 18.15

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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.