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Finding the Fourth Proportional to 403.80, 556.70 and 321.18

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Solution

The fourth proportional to 403.80, 556.70 and 321.18 is: 442.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    403.80 : 556.70 = 321.18 : x
  2. Step 2: Convert to fraction form
    403.80/556.70 = 321.18/x
  3. Step 3: Cross multiply
    403.80x = 556.70 × 321.18
  4. Step 4: Simplify right side
    403.80x = 178,800.91
  5. Step 5: Solve for x
    x = 178,800.91/403.80
  6. Step 6: Final answer
    x = 442.80

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.