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Finding the Fourth Proportional to 821.24, 1,231.41 and 430.31

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Solution

The fourth proportional to 821.24, 1,231.41 and 430.31 is: 645.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.24 : 1,231.41 = 430.31 : x
  2. Step 2: Convert to fraction form
    821.24/1,231.41 = 430.31/x
  3. Step 3: Cross multiply
    821.24x = 1,231.41 × 430.31
  4. Step 4: Simplify right side
    821.24x = 529,881.88
  5. Step 5: Solve for x
    x = 529,881.88/821.24
  6. Step 6: Final answer
    x = 645.23

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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.