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Finding the Fourth Proportional to 491.74, 678.54 and 289.87

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Solution

The fourth proportional to 491.74, 678.54 and 289.87 is: 399.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.74 : 678.54 = 289.87 : x
  2. Step 2: Convert to fraction form
    491.74/678.54 = 289.87/x
  3. Step 3: Cross multiply
    491.74x = 678.54 × 289.87
  4. Step 4: Simplify right side
    491.74x = 196,688.39
  5. Step 5: Solve for x
    x = 196,688.39/491.74
  6. Step 6: Final answer
    x = 399.98

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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.