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Finding the Fourth Proportional to 939.57, 1,409.40 and 290.40

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Solution

The fourth proportional to 939.57, 1,409.40 and 290.40 is: 435.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.57 : 1,409.40 = 290.40 : x
  2. Step 2: Convert to fraction form
    939.57/1,409.40 = 290.40/x
  3. Step 3: Cross multiply
    939.57x = 1,409.40 × 290.40
  4. Step 4: Simplify right side
    939.57x = 409,289.76
  5. Step 5: Solve for x
    x = 409,289.76/939.57
  6. Step 6: Final answer
    x = 435.61

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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.