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Finding the Fourth Proportional to 860.28, 1,289.94 and 339.78

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Solution

The fourth proportional to 860.28, 1,289.94 and 339.78 is: 509.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.28 : 1,289.94 = 339.78 : x
  2. Step 2: Convert to fraction form
    860.28/1,289.94 = 339.78/x
  3. Step 3: Cross multiply
    860.28x = 1,289.94 × 339.78
  4. Step 4: Simplify right side
    860.28x = 438,295.81
  5. Step 5: Solve for x
    x = 438,295.81/860.28
  6. Step 6: Final answer
    x = 509.48

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Double scale
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1.5x scale

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.