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Finding the Fourth Proportional to 690.45, 1,039.15 and 518.04

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Solution

The fourth proportional to 690.45, 1,039.15 and 518.04 is: 779.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.45 : 1,039.15 = 518.04 : x
  2. Step 2: Convert to fraction form
    690.45/1,039.15 = 518.04/x
  3. Step 3: Cross multiply
    690.45x = 1,039.15 × 518.04
  4. Step 4: Simplify right side
    690.45x = 538,321.27
  5. Step 5: Solve for x
    x = 538,321.27/690.45
  6. Step 6: Final answer
    x = 779.67

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.