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Finding the Fourth Proportional to 87.36, 130.91 and 39.21

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Solution

The fourth proportional to 87.36, 130.91 and 39.21 is: 58.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.36 : 130.91 = 39.21 : x
  2. Step 2: Convert to fraction form
    87.36/130.91 = 39.21/x
  3. Step 3: Cross multiply
    87.36x = 130.91 × 39.21
  4. Step 4: Simplify right side
    87.36x = 5,132.79
  5. Step 5: Solve for x
    x = 5,132.79/87.36
  6. Step 6: Final answer
    x = 58.75

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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.