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Finding the Fourth Proportional to 853.19, 1,279.80 and 638.13

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Solution

The fourth proportional to 853.19, 1,279.80 and 638.13 is: 957.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    853.19 : 1,279.80 = 638.13 : x
  2. Step 2: Convert to fraction form
    853.19/1,279.80 = 638.13/x
  3. Step 3: Cross multiply
    853.19x = 1,279.80 × 638.13
  4. Step 4: Simplify right side
    853.19x = 816,678.77
  5. Step 5: Solve for x
    x = 816,678.77/853.19
  6. Step 6: Final answer
    x = 957.21

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.