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Finding the Fourth Proportional to 10.87, 15 and 9.79

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Solution

The fourth proportional to 10.87, 15 and 9.79 is: 13.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    10.87 : 15 = 9.79 : x
  2. Step 2: Convert to fraction form
    10.87/15 = 9.79/x
  3. Step 3: Cross multiply
    10.87x = 15 × 9.79
  4. Step 4: Simplify right side
    10.87x = 146.85
  5. Step 5: Solve for x
    x = 146.85/10.87
  6. Step 6: Final answer
    x = 13.51

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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.