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Finding the Fourth Proportional to 1,378.40, 2,068.40 and 512.80

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Solution

The fourth proportional to 1,378.40, 2,068.40 and 512.80 is: 769.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.40 : 2,068.40 = 512.80 : x
  2. Step 2: Convert to fraction form
    1,378.40/2,068.40 = 512.80/x
  3. Step 3: Cross multiply
    1,378.40x = 2,068.40 × 512.80
  4. Step 4: Simplify right side
    1,378.40x = 1,060,675.52
  5. Step 5: Solve for x
    x = 1,060,675.52/1,378.40
  6. Step 6: Final answer
    x = 769.50

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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.