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Finding the Fourth Proportional to 86.79, 119.66 and 71.59

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Solution

The fourth proportional to 86.79, 119.66 and 71.59 is: 98.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.79 : 119.66 = 71.59 : x
  2. Step 2: Convert to fraction form
    86.79/119.66 = 71.59/x
  3. Step 3: Cross multiply
    86.79x = 119.66 × 71.59
  4. Step 4: Simplify right side
    86.79x = 8,566.46
  5. Step 5: Solve for x
    x = 8,566.46/86.79
  6. Step 6: Final answer
    x = 98.70

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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.