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Finding the Fourth Proportional to 211.65, 317.49 and 89.90

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Solution

The fourth proportional to 211.65, 317.49 and 89.90 is: 134.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.65 : 317.49 = 89.90 : x
  2. Step 2: Convert to fraction form
    211.65/317.49 = 89.90/x
  3. Step 3: Cross multiply
    211.65x = 317.49 × 89.90
  4. Step 4: Simplify right side
    211.65x = 28,540.76
  5. Step 5: Solve for x
    x = 28,540.76/211.65
  6. Step 6: Final answer
    x = 134.85

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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.