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Finding the Fourth Proportional to 15.90, 21.91 and 11.30

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Solution

The fourth proportional to 15.90, 21.91 and 11.30 is: 15.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.90 : 21.91 = 11.30 : x
  2. Step 2: Convert to fraction form
    15.90/21.91 = 11.30/x
  3. Step 3: Cross multiply
    15.90x = 21.91 × 11.30
  4. Step 4: Simplify right side
    15.90x = 247.58
  5. Step 5: Solve for x
    x = 247.58/15.90
  6. Step 6: Final answer
    x = 15.57

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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.