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Finding the Fourth Proportional to 810.54, 1,215.93 and 399.57

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Solution

The fourth proportional to 810.54, 1,215.93 and 399.57 is: 599.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.54 : 1,215.93 = 399.57 : x
  2. Step 2: Convert to fraction form
    810.54/1,215.93 = 399.57/x
  3. Step 3: Cross multiply
    810.54x = 1,215.93 × 399.57
  4. Step 4: Simplify right side
    810.54x = 485,849.15
  5. Step 5: Solve for x
    x = 485,849.15/810.54
  6. Step 6: Final answer
    x = 599.41

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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.