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Finding the Fourth Proportional to 1,081.28, 1,491.80 and 638.88

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Solution

The fourth proportional to 1,081.28, 1,491.80 and 638.88 is: 881.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,081.28 : 1,491.80 = 638.88 : x
  2. Step 2: Convert to fraction form
    1,081.28/1,491.80 = 638.88/x
  3. Step 3: Cross multiply
    1,081.28x = 1,491.80 × 638.88
  4. Step 4: Simplify right side
    1,081.28x = 953,077.99
  5. Step 5: Solve for x
    x = 953,077.99/1,081.28
  6. Step 6: Final answer
    x = 881.44

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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.