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Finding the Fourth Proportional to 823.40, 1,136.12 and 491.60

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Solution

The fourth proportional to 823.40, 1,136.12 and 491.60 is: 678.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    823.40 : 1,136.12 = 491.60 : x
  2. Step 2: Convert to fraction form
    823.40/1,136.12 = 491.60/x
  3. Step 3: Cross multiply
    823.40x = 1,136.12 × 491.60
  4. Step 4: Simplify right side
    823.40x = 558,516.59
  5. Step 5: Solve for x
    x = 558,516.59/823.40
  6. Step 6: Final answer
    x = 678.31

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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.