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Finding the Fourth Proportional to 78.55, 117.85 and 72.23

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Solution

The fourth proportional to 78.55, 117.85 and 72.23 is: 108.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.55 : 117.85 = 72.23 : x
  2. Step 2: Convert to fraction form
    78.55/117.85 = 72.23/x
  3. Step 3: Cross multiply
    78.55x = 117.85 × 72.23
  4. Step 4: Simplify right side
    78.55x = 8,511.69
  5. Step 5: Solve for x
    x = 8,511.69/78.55
  6. Step 6: Final answer
    x = 108.36

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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.