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Finding the Fourth Proportional to 720.31, 993.96 and 405.51

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Solution

The fourth proportional to 720.31, 993.96 and 405.51 is: 559.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.31 : 993.96 = 405.51 : x
  2. Step 2: Convert to fraction form
    720.31/993.96 = 405.51/x
  3. Step 3: Cross multiply
    720.31x = 993.96 × 405.51
  4. Step 4: Simplify right side
    720.31x = 403,060.72
  5. Step 5: Solve for x
    x = 403,060.72/720.31
  6. Step 6: Final answer
    x = 559.57

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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.