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Finding the Fourth Proportional to 720.25, 993.91 and 405.57

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Solution

The fourth proportional to 720.25, 993.91 and 405.57 is: 559.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.25 : 993.91 = 405.57 : x
  2. Step 2: Convert to fraction form
    720.25/993.91 = 405.57/x
  3. Step 3: Cross multiply
    720.25x = 993.91 × 405.57
  4. Step 4: Simplify right side
    720.25x = 403,100.08
  5. Step 5: Solve for x
    x = 403,100.08/720.25
  6. Step 6: Final answer
    x = 559.67

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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.