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Finding the Fourth Proportional to 1,285, 1,772.16 and 812.32

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Solution

The fourth proportional to 1,285, 1,772.16 and 812.32 is: 1,120.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,285 : 1,772.16 = 812.32 : x
  2. Step 2: Convert to fraction form
    1,285/1,772.16 = 812.32/x
  3. Step 3: Cross multiply
    1,285x = 1,772.16 × 812.32
  4. Step 4: Simplify right side
    1,285x = 1,439,561.01
  5. Step 5: Solve for x
    x = 1,439,561.01/1,285
  6. Step 6: Final answer
    x = 1,120.28

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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.