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Finding the Fourth Proportional to 999.21, 1,378.93 and 579.57

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Solution

The fourth proportional to 999.21, 1,378.93 and 579.57 is: 799.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.21 : 1,378.93 = 579.57 : x
  2. Step 2: Convert to fraction form
    999.21/1,378.93 = 579.57/x
  3. Step 3: Cross multiply
    999.21x = 1,378.93 × 579.57
  4. Step 4: Simplify right side
    999.21x = 799,186.46
  5. Step 5: Solve for x
    x = 799,186.46/999.21
  6. Step 6: Final answer
    x = 799.82

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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.