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Finding the Fourth Proportional to 86.87, 119.77 and 72.13

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Solution

The fourth proportional to 86.87, 119.77 and 72.13 is: 99.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.87 : 119.77 = 72.13 : x
  2. Step 2: Convert to fraction form
    86.87/119.77 = 72.13/x
  3. Step 3: Cross multiply
    86.87x = 119.77 × 72.13
  4. Step 4: Simplify right side
    86.87x = 8,639.29
  5. Step 5: Solve for x
    x = 8,639.29/86.87
  6. Step 6: Final answer
    x = 99.45

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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.