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Finding the Fourth Proportional to 1,420.05, 2,129.54 and 640.02

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Solution

The fourth proportional to 1,420.05, 2,129.54 and 640.02 is: 959.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,420.05 : 2,129.54 = 640.02 : x
  2. Step 2: Convert to fraction form
    1,420.05/2,129.54 = 640.02/x
  3. Step 3: Cross multiply
    1,420.05x = 2,129.54 × 640.02
  4. Step 4: Simplify right side
    1,420.05x = 1,362,948.19
  5. Step 5: Solve for x
    x = 1,362,948.19/1,420.05
  6. Step 6: Final answer
    x = 959.79

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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.