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Finding the Fourth Proportional to 86.37, 130.20 and 80.64

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Solution

The fourth proportional to 86.37, 130.20 and 80.64 is: 121.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.37 : 130.20 = 80.64 : x
  2. Step 2: Convert to fraction form
    86.37/130.20 = 80.64/x
  3. Step 3: Cross multiply
    86.37x = 130.20 × 80.64
  4. Step 4: Simplify right side
    86.37x = 10,500.07
  5. Step 5: Solve for x
    x = 10,500.07/86.37
  6. Step 6: Final answer
    x = 121.57

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.