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Finding the Fourth Proportional to 679.99, 1,020.12 and 211.45

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Solution

The fourth proportional to 679.99, 1,020.12 and 211.45 is: 317.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.99 : 1,020.12 = 211.45 : x
  2. Step 2: Convert to fraction form
    679.99/1,020.12 = 211.45/x
  3. Step 3: Cross multiply
    679.99x = 1,020.12 × 211.45
  4. Step 4: Simplify right side
    679.99x = 215,699.27
  5. Step 5: Solve for x
    x = 215,699.27/679.99
  6. Step 6: Final answer
    x = 317.21

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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.