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Finding the Fourth Proportional to 1,420.32, 2,130.72 and 640.30

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Solution

The fourth proportional to 1,420.32, 2,130.72 and 640.30 is: 960.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,420.32 : 2,130.72 = 640.30 : x
  2. Step 2: Convert to fraction form
    1,420.32/2,130.72 = 640.30/x
  3. Step 3: Cross multiply
    1,420.32x = 2,130.72 × 640.30
  4. Step 4: Simplify right side
    1,420.32x = 1,364,302.43
  5. Step 5: Solve for x
    x = 1,364,302.43/1,420.32
  6. Step 6: Final answer
    x = 960.56

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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.