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Finding the Fourth Proportional to 720.50, 994.20 and 405.72

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Solution

The fourth proportional to 720.50, 994.20 and 405.72 is: 559.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.50 : 994.20 = 405.72 : x
  2. Step 2: Convert to fraction form
    720.50/994.20 = 405.72/x
  3. Step 3: Cross multiply
    720.50x = 994.20 × 405.72
  4. Step 4: Simplify right side
    720.50x = 403,366.82
  5. Step 5: Solve for x
    x = 403,366.82/720.50
  6. Step 6: Final answer
    x = 559.84

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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.