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Finding the Fourth Proportional to 189.95, 285.09 and 87.31

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Solution

The fourth proportional to 189.95, 285.09 and 87.31 is: 131.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    189.95 : 285.09 = 87.31 : x
  2. Step 2: Convert to fraction form
    189.95/285.09 = 87.31/x
  3. Step 3: Cross multiply
    189.95x = 285.09 × 87.31
  4. Step 4: Simplify right side
    189.95x = 24,891.24
  5. Step 5: Solve for x
    x = 24,891.24/189.95
  6. Step 6: Final answer
    x = 131.04

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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.