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Finding the Fourth Proportional to 486.95, 671.69 and 389.21

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Solution

The fourth proportional to 486.95, 671.69 and 389.21 is: 536.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.95 : 671.69 = 389.21 : x
  2. Step 2: Convert to fraction form
    486.95/671.69 = 389.21/x
  3. Step 3: Cross multiply
    486.95x = 671.69 × 389.21
  4. Step 4: Simplify right side
    486.95x = 261,426.08
  5. Step 5: Solve for x
    x = 261,426.08/486.95
  6. Step 6: Final answer
    x = 536.87

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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.