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Finding the Fourth Proportional to 698.15, 1,047.20 and 211.21

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Solution

The fourth proportional to 698.15, 1,047.20 and 211.21 is: 316.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    698.15 : 1,047.20 = 211.21 : x
  2. Step 2: Convert to fraction form
    698.15/1,047.20 = 211.21/x
  3. Step 3: Cross multiply
    698.15x = 1,047.20 × 211.21
  4. Step 4: Simplify right side
    698.15x = 221,175.44
  5. Step 5: Solve for x
    x = 221,175.44/698.15
  6. Step 6: Final answer
    x = 316.80

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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.