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Finding the Fourth Proportional to 810.83, 1,215.47 and 685.98

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Solution

The fourth proportional to 810.83, 1,215.47 and 685.98 is: 1,028.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.83 : 1,215.47 = 685.98 : x
  2. Step 2: Convert to fraction form
    810.83/1,215.47 = 685.98/x
  3. Step 3: Cross multiply
    810.83x = 1,215.47 × 685.98
  4. Step 4: Simplify right side
    810.83x = 833,784.68
  5. Step 5: Solve for x
    x = 833,784.68/810.83
  6. Step 6: Final answer
    x = 1,028.32

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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.