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Finding the Fourth Proportional to 87.21, 130.74 and 56.81

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Solution

The fourth proportional to 87.21, 130.74 and 56.81 is: 85.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.21 : 130.74 = 56.81 : x
  2. Step 2: Convert to fraction form
    87.21/130.74 = 56.81/x
  3. Step 3: Cross multiply
    87.21x = 130.74 × 56.81
  4. Step 4: Simplify right side
    87.21x = 7,426.69
  5. Step 5: Solve for x
    x = 7,426.69/87.21
  6. Step 6: Final answer
    x = 85.16

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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.