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Finding the Fourth Proportional to 1,188.80, 1,782.15 and 640.34

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Solution

The fourth proportional to 1,188.80, 1,782.15 and 640.34 is: 959.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,188.80 : 1,782.15 = 640.34 : x
  2. Step 2: Convert to fraction form
    1,188.80/1,782.15 = 640.34/x
  3. Step 3: Cross multiply
    1,188.80x = 1,782.15 × 640.34
  4. Step 4: Simplify right side
    1,188.80x = 1,141,181.93
  5. Step 5: Solve for x
    x = 1,141,181.93/1,188.80
  6. Step 6: Final answer
    x = 959.94

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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.