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Finding the Fourth Proportional to 842.40, 1,166.40 and 820.80

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Solution

The fourth proportional to 842.40, 1,166.40 and 820.80 is: 1,136.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    842.40 : 1,166.40 = 820.80 : x
  2. Step 2: Convert to fraction form
    842.40/1,166.40 = 820.80/x
  3. Step 3: Cross multiply
    842.40x = 1,166.40 × 820.80
  4. Step 4: Simplify right side
    842.40x = 957,381.12
  5. Step 5: Solve for x
    x = 957,381.12/842.40
  6. Step 6: Final answer
    x = 1,136.49

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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.