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Finding the Fourth Proportional to 3,123.80, 4,685.70 and 815.30

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Solution

The fourth proportional to 3,123.80, 4,685.70 and 815.30 is: 1,222.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    3,123.80 : 4,685.70 = 815.30 : x
  2. Step 2: Convert to fraction form
    3,123.80/4,685.70 = 815.30/x
  3. Step 3: Cross multiply
    3,123.80x = 4,685.70 × 815.30
  4. Step 4: Simplify right side
    3,123.80x = 3,820,251.21
  5. Step 5: Solve for x
    x = 3,820,251.21/3,123.80
  6. Step 6: Final answer
    x = 1,222.95

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1.5x scale

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.