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Finding the Fourth Proportional to 486.80, 672.80 and 389.60

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Solution

The fourth proportional to 486.80, 672.80 and 389.60 is: 538.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.80 : 672.80 = 389.60 : x
  2. Step 2: Convert to fraction form
    486.80/672.80 = 389.60/x
  3. Step 3: Cross multiply
    486.80x = 672.80 × 389.60
  4. Step 4: Simplify right side
    486.80x = 262,122.88
  5. Step 5: Solve for x
    x = 262,122.88/486.80
  6. Step 6: Final answer
    x = 538.46

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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.