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Finding the Fourth Proportional to 1,078.86, 1,621 and 689.04

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Solution

The fourth proportional to 1,078.86, 1,621 and 689.04 is: 1,035.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,078.86 : 1,621 = 689.04 : x
  2. Step 2: Convert to fraction form
    1,078.86/1,621 = 689.04/x
  3. Step 3: Cross multiply
    1,078.86x = 1,621 × 689.04
  4. Step 4: Simplify right side
    1,078.86x = 1,116,933.84
  5. Step 5: Solve for x
    x = 1,116,933.84/1,078.86
  6. Step 6: Final answer
    x = 1,035.29

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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.