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Finding the Fourth Proportional to 211.53, 317.08 and 81.50

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Solution

The fourth proportional to 211.53, 317.08 and 81.50 is: 122.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.53 : 317.08 = 81.50 : x
  2. Step 2: Convert to fraction form
    211.53/317.08 = 81.50/x
  3. Step 3: Cross multiply
    211.53x = 317.08 × 81.50
  4. Step 4: Simplify right side
    211.53x = 25,840.03
  5. Step 5: Solve for x
    x = 25,840.03/211.53
  6. Step 6: Final answer
    x = 122.16

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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.