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Finding the Fourth Proportional to 640.98, 884.61 and 491.81

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Solution

The fourth proportional to 640.98, 884.61 and 491.81 is: 678.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.98 : 884.61 = 491.81 : x
  2. Step 2: Convert to fraction form
    640.98/884.61 = 491.81/x
  3. Step 3: Cross multiply
    640.98x = 884.61 × 491.81
  4. Step 4: Simplify right side
    640.98x = 435,055.62
  5. Step 5: Solve for x
    x = 435,055.62/640.98
  6. Step 6: Final answer
    x = 678.74

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.