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Finding the Fourth Proportional to 678.70, 1,018.05 and 245.80

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Solution

The fourth proportional to 678.70, 1,018.05 and 245.80 is: 368.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.70 : 1,018.05 = 245.80 : x
  2. Step 2: Convert to fraction form
    678.70/1,018.05 = 245.80/x
  3. Step 3: Cross multiply
    678.70x = 1,018.05 × 245.80
  4. Step 4: Simplify right side
    678.70x = 250,236.69
  5. Step 5: Solve for x
    x = 250,236.69/678.70
  6. Step 6: Final answer
    x = 368.70

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.