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Finding the Fourth Proportional to 839.60, 1,158.72 and 490.40

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Solution

The fourth proportional to 839.60, 1,158.72 and 490.40 is: 676.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.60 : 1,158.72 = 490.40 : x
  2. Step 2: Convert to fraction form
    839.60/1,158.72 = 490.40/x
  3. Step 3: Cross multiply
    839.60x = 1,158.72 × 490.40
  4. Step 4: Simplify right side
    839.60x = 568,236.29
  5. Step 5: Solve for x
    x = 568,236.29/839.60
  6. Step 6: Final answer
    x = 676.79

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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.