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Finding the Fourth Proportional to 990.84, 1,367.82 and 641.64

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Solution

The fourth proportional to 990.84, 1,367.82 and 641.64 is: 885.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.84 : 1,367.82 = 641.64 : x
  2. Step 2: Convert to fraction form
    990.84/1,367.82 = 641.64/x
  3. Step 3: Cross multiply
    990.84x = 1,367.82 × 641.64
  4. Step 4: Simplify right side
    990.84x = 877,648.02
  5. Step 5: Solve for x
    x = 877,648.02/990.84
  6. Step 6: Final answer
    x = 885.76

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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.