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Finding the Fourth Proportional to 1,319.67, 1,979.64 and 345.78

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Solution

The fourth proportional to 1,319.67, 1,979.64 and 345.78 is: 518.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,319.67 : 1,979.64 = 345.78 : x
  2. Step 2: Convert to fraction form
    1,319.67/1,979.64 = 345.78/x
  3. Step 3: Cross multiply
    1,319.67x = 1,979.64 × 345.78
  4. Step 4: Simplify right side
    1,319.67x = 684,519.92
  5. Step 5: Solve for x
    x = 684,519.92/1,319.67
  6. Step 6: Final answer
    x = 518.71

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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.