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Finding the Fourth Proportional to 720.45, 994.19 and 405.74

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Solution

The fourth proportional to 720.45, 994.19 and 405.74 is: 559.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.45 : 994.19 = 405.74 : x
  2. Step 2: Convert to fraction form
    720.45/994.19 = 405.74/x
  3. Step 3: Cross multiply
    720.45x = 994.19 × 405.74
  4. Step 4: Simplify right side
    720.45x = 403,378.69
  5. Step 5: Solve for x
    x = 403,378.69/720.45
  6. Step 6: Final answer
    x = 559.90

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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.