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Finding the Fourth Proportional to 78.88, 118.40 and 72.20

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Solution

The fourth proportional to 78.88, 118.40 and 72.20 is: 108.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.88 : 118.40 = 72.20 : x
  2. Step 2: Convert to fraction form
    78.88/118.40 = 72.20/x
  3. Step 3: Cross multiply
    78.88x = 118.40 × 72.20
  4. Step 4: Simplify right side
    78.88x = 8,548.48
  5. Step 5: Solve for x
    x = 8,548.48/78.88
  6. Step 6: Final answer
    x = 108.37

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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.