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Finding the Fourth Proportional to 13.70, 18.90 and 10.78

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Solution

The fourth proportional to 13.70, 18.90 and 10.78 is: 14.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.70 : 18.90 = 10.78 : x
  2. Step 2: Convert to fraction form
    13.70/18.90 = 10.78/x
  3. Step 3: Cross multiply
    13.70x = 18.90 × 10.78
  4. Step 4: Simplify right side
    13.70x = 203.74
  5. Step 5: Solve for x
    x = 203.74/13.70
  6. Step 6: Final answer
    x = 14.87

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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.