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Finding the Fourth Proportional to 839.12, 1,158 and 490

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Solution

The fourth proportional to 839.12, 1,158 and 490 is: 676.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.12 : 1,158 = 490 : x
  2. Step 2: Convert to fraction form
    839.12/1,158 = 490/x
  3. Step 3: Cross multiply
    839.12x = 1,158 × 490
  4. Step 4: Simplify right side
    839.12x = 567,420
  5. Step 5: Solve for x
    x = 567,420/839.12
  6. Step 6: Final answer
    x = 676.21

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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.