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Finding the Third Proportional to 7.78 and 8.91

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Solution

The third proportional to 7.78 and 8.91 is: 10.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    7.78 : 8.91 = 8.91 : x
  2. Step 2: Convert to fraction form
    7.78/8.91 = 8.91/x
  3. Step 3: Cross multiply
    7.78x = 8.91 × 8.91
  4. Step 4: Simplify right side
    7.78x = 79.32
  5. Step 5: Solve for x
    x = 79.32/7.78
  6. Step 6: Final answer
    x = 10.19

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Why These Related Problems?

These problems maintain the same ratio (1.14) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.