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Finding the Fourth Proportional to 403.40, 555.90 and 309.80

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Solution

The fourth proportional to 403.40, 555.90 and 309.80 is: 426.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    403.40 : 555.90 = 309.80 : x
  2. Step 2: Convert to fraction form
    403.40/555.90 = 309.80/x
  3. Step 3: Cross multiply
    403.40x = 555.90 × 309.80
  4. Step 4: Simplify right side
    403.40x = 172,217.82
  5. Step 5: Solve for x
    x = 172,217.82/403.40
  6. Step 6: Final answer
    x = 426.92

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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.