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Finding the Fourth Proportional to 720.50, 1,080.50 and 281.72

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Solution

The fourth proportional to 720.50, 1,080.50 and 281.72 is: 422.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.50 : 1,080.50 = 281.72 : x
  2. Step 2: Convert to fraction form
    720.50/1,080.50 = 281.72/x
  3. Step 3: Cross multiply
    720.50x = 1,080.50 × 281.72
  4. Step 4: Simplify right side
    720.50x = 304,393.76
  5. Step 5: Solve for x
    x = 304,393.76/720.50
  6. Step 6: Final answer
    x = 422.48

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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.