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Finding the Fourth Proportional to 1,420.34, 2,130.56 and 640.19

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Solution

The fourth proportional to 1,420.34, 2,130.56 and 640.19 is: 960.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,420.34 : 2,130.56 = 640.19 : x
  2. Step 2: Convert to fraction form
    1,420.34/2,130.56 = 640.19/x
  3. Step 3: Cross multiply
    1,420.34x = 2,130.56 × 640.19
  4. Step 4: Simplify right side
    1,420.34x = 1,363,949.35
  5. Step 5: Solve for x
    x = 1,363,949.35/1,420.34
  6. Step 6: Final answer
    x = 960.30

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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.