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Finding the Fourth Proportional to 1,313.80, 1,970.80 and 339.90

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Solution

The fourth proportional to 1,313.80, 1,970.80 and 339.90 is: 509.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,313.80 : 1,970.80 = 339.90 : x
  2. Step 2: Convert to fraction form
    1,313.80/1,970.80 = 339.90/x
  3. Step 3: Cross multiply
    1,313.80x = 1,970.80 × 339.90
  4. Step 4: Simplify right side
    1,313.80x = 669,874.92
  5. Step 5: Solve for x
    x = 669,874.92/1,313.80
  6. Step 6: Final answer
    x = 509.88

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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.