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Finding the Fourth Proportional to 824.60, 1,237.80 and 642.80

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Solution

The fourth proportional to 824.60, 1,237.80 and 642.80 is: 964.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    824.60 : 1,237.80 = 642.80 : x
  2. Step 2: Convert to fraction form
    824.60/1,237.80 = 642.80/x
  3. Step 3: Cross multiply
    824.60x = 1,237.80 × 642.80
  4. Step 4: Simplify right side
    824.60x = 795,657.84
  5. Step 5: Solve for x
    x = 795,657.84/824.60
  6. Step 6: Final answer
    x = 964.90

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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.