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Finding the Fourth Proportional to 828.23, 1,242.21 and 211.90

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Solution

The fourth proportional to 828.23, 1,242.21 and 211.90 is: 317.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    828.23 : 1,242.21 = 211.90 : x
  2. Step 2: Convert to fraction form
    828.23/1,242.21 = 211.90/x
  3. Step 3: Cross multiply
    828.23x = 1,242.21 × 211.90
  4. Step 4: Simplify right side
    828.23x = 263,223.13
  5. Step 5: Solve for x
    x = 263,223.13/828.23
  6. Step 6: Final answer
    x = 317.81

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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.