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Finding the Fourth Proportional to 879.40, 1,213.57 and 486.42

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Solution

The fourth proportional to 879.40, 1,213.57 and 486.42 is: 671.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    879.40 : 1,213.57 = 486.42 : x
  2. Step 2: Convert to fraction form
    879.40/1,213.57 = 486.42/x
  3. Step 3: Cross multiply
    879.40x = 1,213.57 × 486.42
  4. Step 4: Simplify right side
    879.40x = 590,306.92
  5. Step 5: Solve for x
    x = 590,306.92/879.40
  6. Step 6: Final answer
    x = 671.26

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1.5x scale

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.