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Finding the Fourth Proportional to 19.15, 28.70 and 7.11

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Solution

The fourth proportional to 19.15, 28.70 and 7.11 is: 10.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    19.15 : 28.70 = 7.11 : x
  2. Step 2: Convert to fraction form
    19.15/28.70 = 7.11/x
  3. Step 3: Cross multiply
    19.15x = 28.70 × 7.11
  4. Step 4: Simplify right side
    19.15x = 204.02
  5. Step 5: Solve for x
    x = 204.02/19.15
  6. Step 6: Final answer
    x = 10.66

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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.