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Finding the Fourth Proportional to 491.45, 678.29 and 281.70

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Solution

The fourth proportional to 491.45, 678.29 and 281.70 is: 388.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.45 : 678.29 = 281.70 : x
  2. Step 2: Convert to fraction form
    491.45/678.29 = 281.70/x
  3. Step 3: Cross multiply
    491.45x = 678.29 × 281.70
  4. Step 4: Simplify right side
    491.45x = 191,072.88
  5. Step 5: Solve for x
    x = 191,072.88/491.45
  6. Step 6: Final answer
    x = 388.80

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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.