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Finding the Fourth Proportional to 990.65, 1,367.13 and 641.34

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Solution

The fourth proportional to 990.65, 1,367.13 and 641.34 is: 885.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.65 : 1,367.13 = 641.34 : x
  2. Step 2: Convert to fraction form
    990.65/1,367.13 = 641.34/x
  3. Step 3: Cross multiply
    990.65x = 1,367.13 × 641.34
  4. Step 4: Simplify right side
    990.65x = 876,795.15
  5. Step 5: Solve for x
    x = 876,795.15/990.65
  6. Step 6: Final answer
    x = 885.07

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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.