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Finding the Fourth Proportional to 751.80, 1,122.72 and 642.72

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Solution

The fourth proportional to 751.80, 1,122.72 and 642.72 is: 959.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    751.80 : 1,122.72 = 642.72 : x
  2. Step 2: Convert to fraction form
    751.80/1,122.72 = 642.72/x
  3. Step 3: Cross multiply
    751.80x = 1,122.72 × 642.72
  4. Step 4: Simplify right side
    751.80x = 721,594.60
  5. Step 5: Solve for x
    x = 721,594.60/751.80
  6. Step 6: Final answer
    x = 959.82

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.