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Finding the Fourth Proportional to 720.05, 993.64 and 405.30

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Solution

The fourth proportional to 720.05, 993.64 and 405.30 is: 559.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.05 : 993.64 = 405.30 : x
  2. Step 2: Convert to fraction form
    720.05/993.64 = 405.30/x
  3. Step 3: Cross multiply
    720.05x = 993.64 × 405.30
  4. Step 4: Simplify right side
    720.05x = 402,722.29
  5. Step 5: Solve for x
    x = 402,722.29/720.05
  6. Step 6: Final answer
    x = 559.30

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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.