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Finding the Fourth Proportional to 405.90, 561.60 and 354.30

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Solution

The fourth proportional to 405.90, 561.60 and 354.30 is: 490.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.90 : 561.60 = 354.30 : x
  2. Step 2: Convert to fraction form
    405.90/561.60 = 354.30/x
  3. Step 3: Cross multiply
    405.90x = 561.60 × 354.30
  4. Step 4: Simplify right side
    405.90x = 198,974.88
  5. Step 5: Solve for x
    x = 198,974.88/405.90
  6. Step 6: Final answer
    x = 490.21

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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.