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Finding the Fourth Proportional to 989.87, 1,366.21 and 570.50

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Solution

The fourth proportional to 989.87, 1,366.21 and 570.50 is: 787.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.87 : 1,366.21 = 570.50 : x
  2. Step 2: Convert to fraction form
    989.87/1,366.21 = 570.50/x
  3. Step 3: Cross multiply
    989.87x = 1,366.21 × 570.50
  4. Step 4: Simplify right side
    989.87x = 779,422.81
  5. Step 5: Solve for x
    x = 779,422.81/989.87
  6. Step 6: Final answer
    x = 787.40

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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.