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Finding the Fourth Proportional to 990.80, 1,367.21 and 612.62

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Solution

The fourth proportional to 990.80, 1,367.21 and 612.62 is: 845.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.80 : 1,367.21 = 612.62 : x
  2. Step 2: Convert to fraction form
    990.80/1,367.21 = 612.62/x
  3. Step 3: Cross multiply
    990.80x = 1,367.21 × 612.62
  4. Step 4: Simplify right side
    990.80x = 837,570.29
  5. Step 5: Solve for x
    x = 837,570.29/990.80
  6. Step 6: Final answer
    x = 845.35

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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.