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Finding the Fourth Proportional to 778.12, 1,071.86 and 728.20

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Solution

The fourth proportional to 778.12, 1,071.86 and 728.20 is: 1,003.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    778.12 : 1,071.86 = 728.20 : x
  2. Step 2: Convert to fraction form
    778.12/1,071.86 = 728.20/x
  3. Step 3: Cross multiply
    778.12x = 1,071.86 × 728.20
  4. Step 4: Simplify right side
    778.12x = 780,528.45
  5. Step 5: Solve for x
    x = 780,528.45/778.12
  6. Step 6: Final answer
    x = 1,003.10

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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.