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Finding the Fourth Proportional to 405.69, 559.58 and 318.21

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Solution

The fourth proportional to 405.69, 559.58 and 318.21 is: 438.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.69 : 559.58 = 318.21 : x
  2. Step 2: Convert to fraction form
    405.69/559.58 = 318.21/x
  3. Step 3: Cross multiply
    405.69x = 559.58 × 318.21
  4. Step 4: Simplify right side
    405.69x = 178,062.36
  5. Step 5: Solve for x
    x = 178,062.36/405.69
  6. Step 6: Final answer
    x = 438.91

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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.