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Finding the Fourth Proportional to 939.60, 1,290.60 and 831.60

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Solution

The fourth proportional to 939.60, 1,290.60 and 831.60 is: 1,142.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.60 : 1,290.60 = 831.60 : x
  2. Step 2: Convert to fraction form
    939.60/1,290.60 = 831.60/x
  3. Step 3: Cross multiply
    939.60x = 1,290.60 × 831.60
  4. Step 4: Simplify right side
    939.60x = 1,073,262.96
  5. Step 5: Solve for x
    x = 1,073,262.96/939.60
  6. Step 6: Final answer
    x = 1,142.26

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1.5x scale

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.