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Finding the Fourth Proportional to 990.38, 1,366.85 and 570.65

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Solution

The fourth proportional to 990.38, 1,366.85 and 570.65 is: 787.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.38 : 1,366.85 = 570.65 : x
  2. Step 2: Convert to fraction form
    990.38/1,366.85 = 570.65/x
  3. Step 3: Cross multiply
    990.38x = 1,366.85 × 570.65
  4. Step 4: Simplify right side
    990.38x = 779,987.54
  5. Step 5: Solve for x
    x = 779,987.54/990.38
  6. Step 6: Final answer
    x = 787.56

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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.