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Finding the Fourth Proportional to 1,080.69, 1,491.38 and 638.70

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Solution

The fourth proportional to 1,080.69, 1,491.38 and 638.70 is: 881.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,080.69 : 1,491.38 = 638.70 : x
  2. Step 2: Convert to fraction form
    1,080.69/1,491.38 = 638.70/x
  3. Step 3: Cross multiply
    1,080.69x = 1,491.38 × 638.70
  4. Step 4: Simplify right side
    1,080.69x = 952,541.21
  5. Step 5: Solve for x
    x = 952,541.21/1,080.69
  6. Step 6: Final answer
    x = 881.42

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.