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Finding the Fourth Proportional to 86.15, 118.64 and 77.45

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Solution

The fourth proportional to 86.15, 118.64 and 77.45 is: 106.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.15 : 118.64 = 77.45 : x
  2. Step 2: Convert to fraction form
    86.15/118.64 = 77.45/x
  3. Step 3: Cross multiply
    86.15x = 118.64 × 77.45
  4. Step 4: Simplify right side
    86.15x = 9,187.69
  5. Step 5: Solve for x
    x = 9,187.69/86.15
  6. Step 6: Final answer
    x = 106.65

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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.