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Finding the Fourth Proportional to 680.55, 1,021.36 and 405.81

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Solution

The fourth proportional to 680.55, 1,021.36 and 405.81 is: 609.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.55 : 1,021.36 = 405.81 : x
  2. Step 2: Convert to fraction form
    680.55/1,021.36 = 405.81/x
  3. Step 3: Cross multiply
    680.55x = 1,021.36 × 405.81
  4. Step 4: Simplify right side
    680.55x = 414,477.85
  5. Step 5: Solve for x
    x = 414,477.85/680.55
  6. Step 6: Final answer
    x = 609.03

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.