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Finding the Fourth Proportional to 720.95, 1,081.62 and 258.78

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Solution

The fourth proportional to 720.95, 1,081.62 and 258.78 is: 388.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.95 : 1,081.62 = 258.78 : x
  2. Step 2: Convert to fraction form
    720.95/1,081.62 = 258.78/x
  3. Step 3: Cross multiply
    720.95x = 1,081.62 × 258.78
  4. Step 4: Simplify right side
    720.95x = 279,901.62
  5. Step 5: Solve for x
    x = 279,901.62/720.95
  6. Step 6: Final answer
    x = 388.24

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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.