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Finding the Fourth Proportional to 824.40, 1,233.90 and 640.80

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Solution

The fourth proportional to 824.40, 1,233.90 and 640.80 is: 959.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    824.40 : 1,233.90 = 640.80 : x
  2. Step 2: Convert to fraction form
    824.40/1,233.90 = 640.80/x
  3. Step 3: Cross multiply
    824.40x = 1,233.90 × 640.80
  4. Step 4: Simplify right side
    824.40x = 790,683.12
  5. Step 5: Solve for x
    x = 790,683.12/824.40
  6. Step 6: Final answer
    x = 959.10

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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.