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Finding the Fourth Proportional to 821.15, 1,231.60 and 358.85

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Solution

The fourth proportional to 821.15, 1,231.60 and 358.85 is: 538.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.15 : 1,231.60 = 358.85 : x
  2. Step 2: Convert to fraction form
    821.15/1,231.60 = 358.85/x
  3. Step 3: Cross multiply
    821.15x = 1,231.60 × 358.85
  4. Step 4: Simplify right side
    821.15x = 441,955.42
  5. Step 5: Solve for x
    x = 441,955.42/821.15
  6. Step 6: Final answer
    x = 538.22

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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.