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Finding the Fourth Proportional to 86.02, 118.86 and 78.70

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Solution

The fourth proportional to 86.02, 118.86 and 78.70 is: 108.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.02 : 118.86 = 78.70 : x
  2. Step 2: Convert to fraction form
    86.02/118.86 = 78.70/x
  3. Step 3: Cross multiply
    86.02x = 118.86 × 78.70
  4. Step 4: Simplify right side
    86.02x = 9,354.28
  5. Step 5: Solve for x
    x = 9,354.28/86.02
  6. Step 6: Final answer
    x = 108.75

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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.