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Finding the Fourth Proportional to 839.68, 1,254.69 and 640.92

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Solution

The fourth proportional to 839.68, 1,254.69 and 640.92 is: 957.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.68 : 1,254.69 = 640.92 : x
  2. Step 2: Convert to fraction form
    839.68/1,254.69 = 640.92/x
  3. Step 3: Cross multiply
    839.68x = 1,254.69 × 640.92
  4. Step 4: Simplify right side
    839.68x = 804,155.91
  5. Step 5: Solve for x
    x = 804,155.91/839.68
  6. Step 6: Final answer
    x = 957.69

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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.