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Finding the Fourth Proportional to 990.60, 1,366.92 and 570.86

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Solution

The fourth proportional to 990.60, 1,366.92 and 570.86 is: 787.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.60 : 1,366.92 = 570.86 : x
  2. Step 2: Convert to fraction form
    990.60/1,366.92 = 570.86/x
  3. Step 3: Cross multiply
    990.60x = 1,366.92 × 570.86
  4. Step 4: Simplify right side
    990.60x = 780,319.95
  5. Step 5: Solve for x
    x = 780,319.95/990.60
  6. Step 6: Final answer
    x = 787.72

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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.