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Finding the Fourth Proportional to 990.81, 1,367.31 and 571.01

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Solution

The fourth proportional to 990.81, 1,367.31 and 571.01 is: 787.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.81 : 1,367.31 = 571.01 : x
  2. Step 2: Convert to fraction form
    990.81/1,367.31 = 571.01/x
  3. Step 3: Cross multiply
    990.81x = 1,367.31 × 571.01
  4. Step 4: Simplify right side
    990.81x = 780,737.99
  5. Step 5: Solve for x
    x = 780,737.99/990.81
  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.