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Finding the Fourth Proportional to 990.79, 1,367.13 and 571.07

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Solution

The fourth proportional to 990.79, 1,367.13 and 571.07 is: 787.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.79 : 1,367.13 = 571.07 : x
  2. Step 2: Convert to fraction form
    990.79/1,367.13 = 571.07/x
  3. Step 3: Cross multiply
    990.79x = 1,367.13 × 571.07
  4. Step 4: Simplify right side
    990.79x = 780,726.93
  5. Step 5: Solve for x
    x = 780,726.93/990.79
  6. Step 6: Final answer
    x = 787.98

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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.