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Finding the Fourth Proportional to 405.90, 560.12 and 231.21

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Solution

The fourth proportional to 405.90, 560.12 and 231.21 is: 319.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.90 : 560.12 = 231.21 : x
  2. Step 2: Convert to fraction form
    405.90/560.12 = 231.21/x
  3. Step 3: Cross multiply
    405.90x = 560.12 × 231.21
  4. Step 4: Simplify right side
    405.90x = 129,504.19
  5. Step 5: Solve for x
    x = 129,504.19/405.90
  6. Step 6: Final answer
    x = 319.05

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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.