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Finding the Fourth Proportional to 211.31, 316.81 and 89.61

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Solution

The fourth proportional to 211.31, 316.81 and 89.61 is: 134.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.31 : 316.81 = 89.61 : x
  2. Step 2: Convert to fraction form
    211.31/316.81 = 89.61/x
  3. Step 3: Cross multiply
    211.31x = 316.81 × 89.61
  4. Step 4: Simplify right side
    211.31x = 28,389.34
  5. Step 5: Solve for x
    x = 28,389.34/211.31
  6. Step 6: Final answer
    x = 134.35

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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.