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Finding the Fourth Proportional to 813.07, 1,121.68 and 638.92

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Solution

The fourth proportional to 813.07, 1,121.68 and 638.92 is: 881.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.07 : 1,121.68 = 638.92 : x
  2. Step 2: Convert to fraction form
    813.07/1,121.68 = 638.92/x
  3. Step 3: Cross multiply
    813.07x = 1,121.68 × 638.92
  4. Step 4: Simplify right side
    813.07x = 716,663.79
  5. Step 5: Solve for x
    x = 716,663.79/813.07
  6. Step 6: Final answer
    x = 881.43

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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.