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Finding the Fourth Proportional to 820.99, 1,231.12 and 307.63

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Solution

The fourth proportional to 820.99, 1,231.12 and 307.63 is: 461.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.99 : 1,231.12 = 307.63 : x
  2. Step 2: Convert to fraction form
    820.99/1,231.12 = 307.63/x
  3. Step 3: Cross multiply
    820.99x = 1,231.12 × 307.63
  4. Step 4: Simplify right side
    820.99x = 378,721.75
  5. Step 5: Solve for x
    x = 378,721.75/820.99
  6. Step 6: Final answer
    x = 461.30

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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.