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Finding the Fourth Proportional to 1,280.51, 1,920.36 and 663.80

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Solution

The fourth proportional to 1,280.51, 1,920.36 and 663.80 is: 995.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.51 : 1,920.36 = 663.80 : x
  2. Step 2: Convert to fraction form
    1,280.51/1,920.36 = 663.80/x
  3. Step 3: Cross multiply
    1,280.51x = 1,920.36 × 663.80
  4. Step 4: Simplify right side
    1,280.51x = 1,274,724.12
  5. Step 5: Solve for x
    x = 1,274,724.12/1,280.51
  6. Step 6: Final answer
    x = 995.48

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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.