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Finding the Fourth Proportional to 808.64, 1,115.40 and 621.84

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Solution

The fourth proportional to 808.64, 1,115.40 and 621.84 is: 857.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    808.64 : 1,115.40 = 621.84 : x
  2. Step 2: Convert to fraction form
    808.64/1,115.40 = 621.84/x
  3. Step 3: Cross multiply
    808.64x = 1,115.40 × 621.84
  4. Step 4: Simplify right side
    808.64x = 693,600.34
  5. Step 5: Solve for x
    x = 693,600.34/808.64
  6. Step 6: Final answer
    x = 857.74

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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.