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Finding the Fourth Proportional to 851.43, 1,275.35 and 643.71

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Solution

The fourth proportional to 851.43, 1,275.35 and 643.71 is: 964.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    851.43 : 1,275.35 = 643.71 : x
  2. Step 2: Convert to fraction form
    851.43/1,275.35 = 643.71/x
  3. Step 3: Cross multiply
    851.43x = 1,275.35 × 643.71
  4. Step 4: Simplify right side
    851.43x = 820,952.33
  5. Step 5: Solve for x
    x = 820,952.33/851.43
  6. Step 6: Final answer
    x = 964.20

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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.