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Finding the Fourth Proportional to 1,420.34, 2,129.02 and 689.51

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Solution

The fourth proportional to 1,420.34, 2,129.02 and 689.51 is: 1,033.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,420.34 : 2,129.02 = 689.51 : x
  2. Step 2: Convert to fraction form
    1,420.34/2,129.02 = 689.51/x
  3. Step 3: Cross multiply
    1,420.34x = 2,129.02 × 689.51
  4. Step 4: Simplify right side
    1,420.34x = 1,467,984.18
  5. Step 5: Solve for x
    x = 1,467,984.18/1,420.34
  6. Step 6: Final answer
    x = 1,033.55

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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.