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Finding the Fourth Proportional to 1,319, 1,978.50 and 407

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Solution

The fourth proportional to 1,319, 1,978.50 and 407 is: 610.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,319 : 1,978.50 = 407 : x
  2. Step 2: Convert to fraction form
    1,319/1,978.50 = 407/x
  3. Step 3: Cross multiply
    1,319x = 1,978.50 × 407
  4. Step 4: Simplify right side
    1,319x = 805,249.50
  5. Step 5: Solve for x
    x = 805,249.50/1,319
  6. Step 6: Final answer
    x = 610.50

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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.