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Finding the Fourth Proportional to 990.32, 1,366.39 and 570.79

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Solution

The fourth proportional to 990.32, 1,366.39 and 570.79 is: 787.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.32 : 1,366.39 = 570.79 : x
  2. Step 2: Convert to fraction form
    990.32/1,366.39 = 570.79/x
  3. Step 3: Cross multiply
    990.32x = 1,366.39 × 570.79
  4. Step 4: Simplify right side
    990.32x = 779,918.89
  5. Step 5: Solve for x
    x = 779,918.89/990.32
  6. Step 6: Final answer
    x = 787.55

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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.