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Finding the Fourth Proportional to 874.90, 1,309.50 and 643.71

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Solution

The fourth proportional to 874.90, 1,309.50 and 643.71 is: 963.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    874.90 : 1,309.50 = 643.71 : x
  2. Step 2: Convert to fraction form
    874.90/1,309.50 = 643.71/x
  3. Step 3: Cross multiply
    874.90x = 1,309.50 × 643.71
  4. Step 4: Simplify right side
    874.90x = 842,943.16
  5. Step 5: Solve for x
    x = 842,943.16/874.90
  6. Step 6: Final answer
    x = 963.47

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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.