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Finding the Fourth Proportional to 1,313.20, 1,970.70 and 728.20

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Solution

The fourth proportional to 1,313.20, 1,970.70 and 728.20 is: 1,092.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,313.20 : 1,970.70 = 728.20 : x
  2. Step 2: Convert to fraction form
    1,313.20/1,970.70 = 728.20/x
  3. Step 3: Cross multiply
    1,313.20x = 1,970.70 × 728.20
  4. Step 4: Simplify right side
    1,313.20x = 1,435,063.74
  5. Step 5: Solve for x
    x = 1,435,063.74/1,313.20
  6. Step 6: Final answer
    x = 1,092.80

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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.