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Finding the Fourth Proportional to 403.18, 556.70 and 309.78

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Solution

The fourth proportional to 403.18, 556.70 and 309.78 is: 427.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    403.18 : 556.70 = 309.78 : x
  2. Step 2: Convert to fraction form
    403.18/556.70 = 309.78/x
  3. Step 3: Cross multiply
    403.18x = 556.70 × 309.78
  4. Step 4: Simplify right side
    403.18x = 172,453.91
  5. Step 5: Solve for x
    x = 172,453.91/403.18
  6. Step 6: Final answer
    x = 427.73

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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.