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Finding the Fourth Proportional to 872.70, 1,309.35 and 385.77

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Solution

The fourth proportional to 872.70, 1,309.35 and 385.77 is: 578.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    872.70 : 1,309.35 = 385.77 : x
  2. Step 2: Convert to fraction form
    872.70/1,309.35 = 385.77/x
  3. Step 3: Cross multiply
    872.70x = 1,309.35 × 385.77
  4. Step 4: Simplify right side
    872.70x = 505,107.95
  5. Step 5: Solve for x
    x = 505,107.95/872.70
  6. Step 6: Final answer
    x = 578.79

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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.