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Finding the Fourth Proportional to 1,305.12, 1,800.80 and 781.04

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Solution

The fourth proportional to 1,305.12, 1,800.80 and 781.04 is: 1,077.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,305.12 : 1,800.80 = 781.04 : x
  2. Step 2: Convert to fraction form
    1,305.12/1,800.80 = 781.04/x
  3. Step 3: Cross multiply
    1,305.12x = 1,800.80 × 781.04
  4. Step 4: Simplify right side
    1,305.12x = 1,406,496.83
  5. Step 5: Solve for x
    x = 1,406,496.83/1,305.12
  6. Step 6: Final answer
    x = 1,077.68

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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.