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Finding the Fourth Proportional to 405.40, 559.20 and 318.28

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Solution

The fourth proportional to 405.40, 559.20 and 318.28 is: 439.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.40 : 559.20 = 318.28 : x
  2. Step 2: Convert to fraction form
    405.40/559.20 = 318.28/x
  3. Step 3: Cross multiply
    405.40x = 559.20 × 318.28
  4. Step 4: Simplify right side
    405.40x = 177,982.18
  5. Step 5: Solve for x
    x = 177,982.18/405.40
  6. Step 6: Final answer
    x = 439.03

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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.