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Finding the Fourth Proportional to 720.51, 994.26 and 405.78

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Solution

The fourth proportional to 720.51, 994.26 and 405.78 is: 559.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.51 : 994.26 = 405.78 : x
  2. Step 2: Convert to fraction form
    720.51/994.26 = 405.78/x
  3. Step 3: Cross multiply
    720.51x = 994.26 × 405.78
  4. Step 4: Simplify right side
    720.51x = 403,450.82
  5. Step 5: Solve for x
    x = 403,450.82/720.51
  6. Step 6: Final answer
    x = 559.95

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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.