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Finding the Fourth Proportional to 810.61, 1,215.71 and 323.39

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Solution

The fourth proportional to 810.61, 1,215.71 and 323.39 is: 485.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.61 : 1,215.71 = 323.39 : x
  2. Step 2: Convert to fraction form
    810.61/1,215.71 = 323.39/x
  3. Step 3: Cross multiply
    810.61x = 1,215.71 × 323.39
  4. Step 4: Simplify right side
    810.61x = 393,151.09
  5. Step 5: Solve for x
    x = 393,151.09/810.61
  6. Step 6: Final answer
    x = 485.01

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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.