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Finding the Fourth Proportional to 720.40, 994.14 and 405.67

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Solution

The fourth proportional to 720.40, 994.14 and 405.67 is: 559.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.40 : 994.14 = 405.67 : x
  2. Step 2: Convert to fraction form
    720.40/994.14 = 405.67/x
  3. Step 3: Cross multiply
    720.40x = 994.14 × 405.67
  4. Step 4: Simplify right side
    720.40x = 403,287.80
  5. Step 5: Solve for x
    x = 403,287.80/720.40
  6. Step 6: Final answer
    x = 559.81

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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.