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Finding the Fourth Proportional to 1,319.16, 1,978.85 and 394.65

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Solution

The fourth proportional to 1,319.16, 1,978.85 and 394.65 is: 592.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,319.16 : 1,978.85 = 394.65 : x
  2. Step 2: Convert to fraction form
    1,319.16/1,978.85 = 394.65/x
  3. Step 3: Cross multiply
    1,319.16x = 1,978.85 × 394.65
  4. Step 4: Simplify right side
    1,319.16x = 780,953.15
  5. Step 5: Solve for x
    x = 780,953.15/1,319.16
  6. Step 6: Final answer
    x = 592.01

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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.