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Finding the Fourth Proportional to 817.20, 1,127.70 and 485.43

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Solution

The fourth proportional to 817.20, 1,127.70 and 485.43 is: 669.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.20 : 1,127.70 = 485.43 : x
  2. Step 2: Convert to fraction form
    817.20/1,127.70 = 485.43/x
  3. Step 3: Cross multiply
    817.20x = 1,127.70 × 485.43
  4. Step 4: Simplify right side
    817.20x = 547,419.41
  5. Step 5: Solve for x
    x = 547,419.41/817.20
  6. Step 6: Final answer
    x = 669.87

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1.5x scale

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.