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Finding the Fourth Proportional to 879.21, 1,213.17 and 486.15

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Solution

The fourth proportional to 879.21, 1,213.17 and 486.15 is: 670.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    879.21 : 1,213.17 = 486.15 : x
  2. Step 2: Convert to fraction form
    879.21/1,213.17 = 486.15/x
  3. Step 3: Cross multiply
    879.21x = 1,213.17 × 486.15
  4. Step 4: Simplify right side
    879.21x = 589,782.60
  5. Step 5: Solve for x
    x = 589,782.60/879.21
  6. Step 6: Final answer
    x = 670.81

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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.