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Finding the Fourth Proportional to 86.02, 118.78 and 72.20

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Solution

The fourth proportional to 86.02, 118.78 and 72.20 is: 99.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.02 : 118.78 = 72.20 : x
  2. Step 2: Convert to fraction form
    86.02/118.78 = 72.20/x
  3. Step 3: Cross multiply
    86.02x = 118.78 × 72.20
  4. Step 4: Simplify right side
    86.02x = 8,575.92
  5. Step 5: Solve for x
    x = 8,575.92/86.02
  6. Step 6: Final answer
    x = 99.70

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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.