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Finding the Fourth Proportional to 720.31, 1,079.95 and 281.22

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Solution

The fourth proportional to 720.31, 1,079.95 and 281.22 is: 421.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.31 : 1,079.95 = 281.22 : x
  2. Step 2: Convert to fraction form
    720.31/1,079.95 = 281.22/x
  3. Step 3: Cross multiply
    720.31x = 1,079.95 × 281.22
  4. Step 4: Simplify right side
    720.31x = 303,703.54
  5. Step 5: Solve for x
    x = 303,703.54/720.31
  6. Step 6: Final answer
    x = 421.63

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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.