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Finding the Fourth Proportional to 809.40, 1,215.32 and 646.60

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Solution

The fourth proportional to 809.40, 1,215.32 and 646.60 is: 970.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.40 : 1,215.32 = 646.60 : x
  2. Step 2: Convert to fraction form
    809.40/1,215.32 = 646.60/x
  3. Step 3: Cross multiply
    809.40x = 1,215.32 × 646.60
  4. Step 4: Simplify right side
    809.40x = 785,825.91
  5. Step 5: Solve for x
    x = 785,825.91/809.40
  6. Step 6: Final answer
    x = 970.87

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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.