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Finding the Fourth Proportional to 720.21, 993.93 and 405.57

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Solution

The fourth proportional to 720.21, 993.93 and 405.57 is: 559.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.21 : 993.93 = 405.57 : x
  2. Step 2: Convert to fraction form
    720.21/993.93 = 405.57/x
  3. Step 3: Cross multiply
    720.21x = 993.93 × 405.57
  4. Step 4: Simplify right side
    720.21x = 403,108.19
  5. Step 5: Solve for x
    x = 403,108.19/720.21
  6. Step 6: Final answer
    x = 559.71

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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.