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Finding the Fourth Proportional to 751.40, 1,128.90 and 672.20

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Solution

The fourth proportional to 751.40, 1,128.90 and 672.20 is: 1,009.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    751.40 : 1,128.90 = 672.20 : x
  2. Step 2: Convert to fraction form
    751.40/1,128.90 = 672.20/x
  3. Step 3: Cross multiply
    751.40x = 1,128.90 × 672.20
  4. Step 4: Simplify right side
    751.40x = 758,846.58
  5. Step 5: Solve for x
    x = 758,846.58/751.40
  6. Step 6: Final answer
    x = 1,009.91

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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.