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Finding the Fourth Proportional to 78.10, 106.99 and 77.22

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Solution

The fourth proportional to 78.10, 106.99 and 77.22 is: 105.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.10 : 106.99 = 77.22 : x
  2. Step 2: Convert to fraction form
    78.10/106.99 = 77.22/x
  3. Step 3: Cross multiply
    78.10x = 106.99 × 77.22
  4. Step 4: Simplify right side
    78.10x = 8,261.57
  5. Step 5: Solve for x
    x = 8,261.57/78.10
  6. Step 6: Final answer
    x = 105.79

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.