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Finding the Fourth Proportional to 921.60, 1,379.94 and 812.28

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Solution

The fourth proportional to 921.60, 1,379.94 and 812.28 is: 1,216.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.60 : 1,379.94 = 812.28 : x
  2. Step 2: Convert to fraction form
    921.60/1,379.94 = 812.28/x
  3. Step 3: Cross multiply
    921.60x = 1,379.94 × 812.28
  4. Step 4: Simplify right side
    921.60x = 1,120,897.66
  5. Step 5: Solve for x
    x = 1,120,897.66/921.60
  6. Step 6: Final answer
    x = 1,216.25

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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.