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Finding the Fourth Proportional to 86.66, 119.50 and 65.90

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Solution

The fourth proportional to 86.66, 119.50 and 65.90 is: 90.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.66 : 119.50 = 65.90 : x
  2. Step 2: Convert to fraction form
    86.66/119.50 = 65.90/x
  3. Step 3: Cross multiply
    86.66x = 119.50 × 65.90
  4. Step 4: Simplify right side
    86.66x = 7,875.05
  5. Step 5: Solve for x
    x = 7,875.05/86.66
  6. Step 6: Final answer
    x = 90.87

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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.