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Finding the Fourth Proportional to 823.40, 1,136.20 and 491.92

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Solution

The fourth proportional to 823.40, 1,136.20 and 491.92 is: 678.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    823.40 : 1,136.20 = 491.92 : x
  2. Step 2: Convert to fraction form
    823.40/1,136.20 = 491.92/x
  3. Step 3: Cross multiply
    823.40x = 1,136.20 × 491.92
  4. Step 4: Simplify right side
    823.40x = 558,919.50
  5. Step 5: Solve for x
    x = 558,919.50/823.40
  6. Step 6: Final answer
    x = 678.79

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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.