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Finding the Fourth Proportional to 1,287.39, 1,930.71 and 628.86

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Solution

The fourth proportional to 1,287.39, 1,930.71 and 628.86 is: 943.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.39 : 1,930.71 = 628.86 : x
  2. Step 2: Convert to fraction form
    1,287.39/1,930.71 = 628.86/x
  3. Step 3: Cross multiply
    1,287.39x = 1,930.71 × 628.86
  4. Step 4: Simplify right side
    1,287.39x = 1,214,146.29
  5. Step 5: Solve for x
    x = 1,214,146.29/1,287.39
  6. Step 6: Final answer
    x = 943.11

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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.