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Finding the Fourth Proportional to 874.22, 1,309.89 and 643.58

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Solution

The fourth proportional to 874.22, 1,309.89 and 643.58 is: 964.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    874.22 : 1,309.89 = 643.58 : x
  2. Step 2: Convert to fraction form
    874.22/1,309.89 = 643.58/x
  3. Step 3: Cross multiply
    874.22x = 1,309.89 × 643.58
  4. Step 4: Simplify right side
    874.22x = 843,019.01
  5. Step 5: Solve for x
    x = 843,019.01/874.22
  6. Step 6: Final answer
    x = 964.31

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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.