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Finding the Fourth Proportional to 1,239.10, 1,859.70 and 509.20

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Solution

The fourth proportional to 1,239.10, 1,859.70 and 509.20 is: 764.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,239.10 : 1,859.70 = 509.20 : x
  2. Step 2: Convert to fraction form
    1,239.10/1,859.70 = 509.20/x
  3. Step 3: Cross multiply
    1,239.10x = 1,859.70 × 509.20
  4. Step 4: Simplify right side
    1,239.10x = 946,959.24
  5. Step 5: Solve for x
    x = 946,959.24/1,239.10
  6. Step 6: Final answer
    x = 764.23

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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.