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Finding the Fourth Proportional to 86.57, 119.37 and 65.78

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Solution

The fourth proportional to 86.57, 119.37 and 65.78 is: 90.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.57 : 119.37 = 65.78 : x
  2. Step 2: Convert to fraction form
    86.57/119.37 = 65.78/x
  3. Step 3: Cross multiply
    86.57x = 119.37 × 65.78
  4. Step 4: Simplify right side
    86.57x = 7,852.16
  5. Step 5: Solve for x
    x = 7,852.16/86.57
  6. Step 6: Final answer
    x = 90.70

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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.