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Finding the Fourth Proportional to 86.41, 129.75 and 52.21

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Solution

The fourth proportional to 86.41, 129.75 and 52.21 is: 78.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.41 : 129.75 = 52.21 : x
  2. Step 2: Convert to fraction form
    86.41/129.75 = 52.21/x
  3. Step 3: Cross multiply
    86.41x = 129.75 × 52.21
  4. Step 4: Simplify right side
    86.41x = 6,774.25
  5. Step 5: Solve for x
    x = 6,774.25/86.41
  6. Step 6: Final answer
    x = 78.40

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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.