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Finding the Fourth Proportional to 720.34, 1,078.81 and 445.60

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Solution

The fourth proportional to 720.34, 1,078.81 and 445.60 is: 667.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.34 : 1,078.81 = 445.60 : x
  2. Step 2: Convert to fraction form
    720.34/1,078.81 = 445.60/x
  3. Step 3: Cross multiply
    720.34x = 1,078.81 × 445.60
  4. Step 4: Simplify right side
    720.34x = 480,717.34
  5. Step 5: Solve for x
    x = 480,717.34/720.34
  6. Step 6: Final answer
    x = 667.34

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.