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Finding the Fourth Proportional to 1,328.57, 1,990.36 and 779.12

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Solution

The fourth proportional to 1,328.57, 1,990.36 and 779.12 is: 1,167.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,328.57 : 1,990.36 = 779.12 : x
  2. Step 2: Convert to fraction form
    1,328.57/1,990.36 = 779.12/x
  3. Step 3: Cross multiply
    1,328.57x = 1,990.36 × 779.12
  4. Step 4: Simplify right side
    1,328.57x = 1,550,729.28
  5. Step 5: Solve for x
    x = 1,550,729.28/1,328.57
  6. Step 6: Final answer
    x = 1,167.22

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.