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Finding the Fourth Proportional to 810.32, 1,214.90 and 399.36

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Solution

The fourth proportional to 810.32, 1,214.90 and 399.36 is: 598.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.32 : 1,214.90 = 399.36 : x
  2. Step 2: Convert to fraction form
    810.32/1,214.90 = 399.36/x
  3. Step 3: Cross multiply
    810.32x = 1,214.90 × 399.36
  4. Step 4: Simplify right side
    810.32x = 485,180.47
  5. Step 5: Solve for x
    x = 485,180.47/810.32
  6. Step 6: Final answer
    x = 598.76

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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.