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Finding the Fourth Proportional to 816.78, 1,127.06 and 485.29

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Solution

The fourth proportional to 816.78, 1,127.06 and 485.29 is: 669.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    816.78 : 1,127.06 = 485.29 : x
  2. Step 2: Convert to fraction form
    816.78/1,127.06 = 485.29/x
  3. Step 3: Cross multiply
    816.78x = 1,127.06 × 485.29
  4. Step 4: Simplify right side
    816.78x = 546,954.48
  5. Step 5: Solve for x
    x = 546,954.48/816.78
  6. Step 6: Final answer
    x = 669.64

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.