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Finding the Fourth Proportional to 86.55, 129.83 and 28.78

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Solution

The fourth proportional to 86.55, 129.83 and 28.78 is: 43.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.55 : 129.83 = 28.78 : x
  2. Step 2: Convert to fraction form
    86.55/129.83 = 28.78/x
  3. Step 3: Cross multiply
    86.55x = 129.83 × 28.78
  4. Step 4: Simplify right side
    86.55x = 3,736.51
  5. Step 5: Solve for x
    x = 3,736.51/86.55
  6. Step 6: Final answer
    x = 43.17

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.