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Finding the Fourth Proportional to 810.30, 1,215.27 and 393.82

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Solution

The fourth proportional to 810.30, 1,215.27 and 393.82 is: 590.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.30 : 1,215.27 = 393.82 : x
  2. Step 2: Convert to fraction form
    810.30/1,215.27 = 393.82/x
  3. Step 3: Cross multiply
    810.30x = 1,215.27 × 393.82
  4. Step 4: Simplify right side
    810.30x = 478,597.63
  5. Step 5: Solve for x
    x = 478,597.63/810.30
  6. Step 6: Final answer
    x = 590.64

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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.