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Finding the Fourth Proportional to 720.79, 1,078.54 and 460.78

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Solution

The fourth proportional to 720.79, 1,078.54 and 460.78 is: 689.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.79 : 1,078.54 = 460.78 : x
  2. Step 2: Convert to fraction form
    720.79/1,078.54 = 460.78/x
  3. Step 3: Cross multiply
    720.79x = 1,078.54 × 460.78
  4. Step 4: Simplify right side
    720.79x = 496,969.66
  5. Step 5: Solve for x
    x = 496,969.66/720.79
  6. Step 6: Final answer
    x = 689.48

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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.