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Finding the Fourth Proportional to 211.45, 317.15 and 72.61

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Solution

The fourth proportional to 211.45, 317.15 and 72.61 is: 108.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.45 : 317.15 = 72.61 : x
  2. Step 2: Convert to fraction form
    211.45/317.15 = 72.61/x
  3. Step 3: Cross multiply
    211.45x = 317.15 × 72.61
  4. Step 4: Simplify right side
    211.45x = 23,028.26
  5. Step 5: Solve for x
    x = 23,028.26/211.45
  6. Step 6: Final answer
    x = 108.91

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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.