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Finding the Fourth Proportional to 211.85, 317.72 and 90.09

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Solution

The fourth proportional to 211.85, 317.72 and 90.09 is: 135.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.85 : 317.72 = 90.09 : x
  2. Step 2: Convert to fraction form
    211.85/317.72 = 90.09/x
  3. Step 3: Cross multiply
    211.85x = 317.72 × 90.09
  4. Step 4: Simplify right side
    211.85x = 28,622.94
  5. Step 5: Solve for x
    x = 28,622.94/211.85
  6. Step 6: Final answer
    x = 135.11

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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.