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Finding the Fourth Proportional to 78.32, 108.20 and 72.92

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Solution

The fourth proportional to 78.32, 108.20 and 72.92 is: 100.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.32 : 108.20 = 72.92 : x
  2. Step 2: Convert to fraction form
    78.32/108.20 = 72.92/x
  3. Step 3: Cross multiply
    78.32x = 108.20 × 72.92
  4. Step 4: Simplify right side
    78.32x = 7,889.94
  5. Step 5: Solve for x
    x = 7,889.94/78.32
  6. Step 6: Final answer
    x = 100.74

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.