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Finding the Fourth Proportional to 813.42, 1,121.28 and 638.46

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Solution

The fourth proportional to 813.42, 1,121.28 and 638.46 is: 880.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.42 : 1,121.28 = 638.46 : x
  2. Step 2: Convert to fraction form
    813.42/1,121.28 = 638.46/x
  3. Step 3: Cross multiply
    813.42x = 1,121.28 × 638.46
  4. Step 4: Simplify right side
    813.42x = 715,892.43
  5. Step 5: Solve for x
    x = 715,892.43/813.42
  6. Step 6: Final answer
    x = 880.10

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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.