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Finding the Fourth Proportional to 86.63, 119.66 and 76.31

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Solution

The fourth proportional to 86.63, 119.66 and 76.31 is: 105.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.63 : 119.66 = 76.31 : x
  2. Step 2: Convert to fraction form
    86.63/119.66 = 76.31/x
  3. Step 3: Cross multiply
    86.63x = 119.66 × 76.31
  4. Step 4: Simplify right side
    86.63x = 9,130.66
  5. Step 5: Solve for x
    x = 9,130.66/86.63
  6. Step 6: Final answer
    x = 105.40

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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.