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Finding the Fourth Proportional to 821.63, 1,230.44 and 431.96

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Solution

The fourth proportional to 821.63, 1,230.44 and 431.96 is: 646.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.63 : 1,230.44 = 431.96 : x
  2. Step 2: Convert to fraction form
    821.63/1,230.44 = 431.96/x
  3. Step 3: Cross multiply
    821.63x = 1,230.44 × 431.96
  4. Step 4: Simplify right side
    821.63x = 531,492.55
  5. Step 5: Solve for x
    x = 531,492.55/821.63
  6. Step 6: Final answer
    x = 646.88

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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.