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Finding the Fourth Proportional to 1,239, 1,709.35 and 819.55

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Solution

The fourth proportional to 1,239, 1,709.35 and 819.55 is: 1,130.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,239 : 1,709.35 = 819.55 : x
  2. Step 2: Convert to fraction form
    1,239/1,709.35 = 819.55/x
  3. Step 3: Cross multiply
    1,239x = 1,709.35 × 819.55
  4. Step 4: Simplify right side
    1,239x = 1,400,897.79
  5. Step 5: Solve for x
    x = 1,400,897.79/1,239
  6. Step 6: Final answer
    x = 1,130.67

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.