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Finding the Fourth Proportional to 15.90, 23.80 and 12.47

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Solution

The fourth proportional to 15.90, 23.80 and 12.47 is: 18.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.90 : 23.80 = 12.47 : x
  2. Step 2: Convert to fraction form
    15.90/23.80 = 12.47/x
  3. Step 3: Cross multiply
    15.90x = 23.80 × 12.47
  4. Step 4: Simplify right side
    15.90x = 296.79
  5. Step 5: Solve for x
    x = 296.79/15.90
  6. Step 6: Final answer
    x = 18.67

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.