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Finding the Fourth Proportional to 810.38, 1,215.58 and 649.09

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Solution

The fourth proportional to 810.38, 1,215.58 and 649.09 is: 973.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.38 : 1,215.58 = 649.09 : x
  2. Step 2: Convert to fraction form
    810.38/1,215.58 = 649.09/x
  3. Step 3: Cross multiply
    810.38x = 1,215.58 × 649.09
  4. Step 4: Simplify right side
    810.38x = 789,020.82
  5. Step 5: Solve for x
    x = 789,020.82/810.38
  6. Step 6: Final answer
    x = 973.64

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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.