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Finding the Fourth Proportional to 810.18, 1,215.63 and 399.33

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Solution

The fourth proportional to 810.18, 1,215.63 and 399.33 is: 599.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.18 : 1,215.63 = 399.33 : x
  2. Step 2: Convert to fraction form
    810.18/1,215.63 = 399.33/x
  3. Step 3: Cross multiply
    810.18x = 1,215.63 × 399.33
  4. Step 4: Simplify right side
    810.18x = 485,437.53
  5. Step 5: Solve for x
    x = 485,437.53/810.18
  6. Step 6: Final answer
    x = 599.17

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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.