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Finding the Fourth Proportional to 810.21, 1,215 and 679.60

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Solution

The fourth proportional to 810.21, 1,215 and 679.60 is: 1,019.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.21 : 1,215 = 679.60 : x
  2. Step 2: Convert to fraction form
    810.21/1,215 = 679.60/x
  3. Step 3: Cross multiply
    810.21x = 1,215 × 679.60
  4. Step 4: Simplify right side
    810.21x = 825,714
  5. Step 5: Solve for x
    x = 825,714/810.21
  6. Step 6: Final answer
    x = 1,019.14

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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.