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Finding the Fourth Proportional to 1,280.50, 1,767.10 and 728.50

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Solution

The fourth proportional to 1,280.50, 1,767.10 and 728.50 is: 1,005.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.50 : 1,767.10 = 728.50 : x
  2. Step 2: Convert to fraction form
    1,280.50/1,767.10 = 728.50/x
  3. Step 3: Cross multiply
    1,280.50x = 1,767.10 × 728.50
  4. Step 4: Simplify right side
    1,280.50x = 1,287,332.35
  5. Step 5: Solve for x
    x = 1,287,332.35/1,280.50
  6. Step 6: Final answer
    x = 1,005.34

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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.