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Finding the Fourth Proportional to 207.18, 310.65 and 78.78

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Solution

The fourth proportional to 207.18, 310.65 and 78.78 is: 118.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    207.18 : 310.65 = 78.78 : x
  2. Step 2: Convert to fraction form
    207.18/310.65 = 78.78/x
  3. Step 3: Cross multiply
    207.18x = 310.65 × 78.78
  4. Step 4: Simplify right side
    207.18x = 24,473.01
  5. Step 5: Solve for x
    x = 24,473.01/207.18
  6. Step 6: Final answer
    x = 118.12

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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.