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Finding the Fourth Proportional to 356.40, 489.60 and 290.70

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Solution

The fourth proportional to 356.40, 489.60 and 290.70 is: 399.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    356.40 : 489.60 = 290.70 : x
  2. Step 2: Convert to fraction form
    356.40/489.60 = 290.70/x
  3. Step 3: Cross multiply
    356.40x = 489.60 × 290.70
  4. Step 4: Simplify right side
    356.40x = 142,326.72
  5. Step 5: Solve for x
    x = 142,326.72/356.40
  6. Step 6: Final answer
    x = 399.35

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.