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Finding the Fourth Proportional to 813.91, 1,122.47 and 638.95

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Solution

The fourth proportional to 813.91, 1,122.47 and 638.95 is: 881.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.91 : 1,122.47 = 638.95 : x
  2. Step 2: Convert to fraction form
    813.91/1,122.47 = 638.95/x
  3. Step 3: Cross multiply
    813.91x = 1,122.47 × 638.95
  4. Step 4: Simplify right side
    813.91x = 717,198.60
  5. Step 5: Solve for x
    x = 717,198.60/813.91
  6. Step 6: Final answer
    x = 881.18

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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.