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Finding the Fourth Proportional to 1,187.02, 1,638.46 and 689.90

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Solution

The fourth proportional to 1,187.02, 1,638.46 and 689.90 is: 952.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,187.02 : 1,638.46 = 689.90 : x
  2. Step 2: Convert to fraction form
    1,187.02/1,638.46 = 689.90/x
  3. Step 3: Cross multiply
    1,187.02x = 1,638.46 × 689.90
  4. Step 4: Simplify right side
    1,187.02x = 1,130,373.55
  5. Step 5: Solve for x
    x = 1,130,373.55/1,187.02
  6. Step 6: Final answer
    x = 952.28

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.