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Finding the Fourth Proportional to 1,187.25, 1,638.30 and 689.89

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Solution

The fourth proportional to 1,187.25, 1,638.30 and 689.89 is: 951.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,187.25 : 1,638.30 = 689.89 : x
  2. Step 2: Convert to fraction form
    1,187.25/1,638.30 = 689.89/x
  3. Step 3: Cross multiply
    1,187.25x = 1,638.30 × 689.89
  4. Step 4: Simplify right side
    1,187.25x = 1,130,235.15
  5. Step 5: Solve for x
    x = 1,130,235.15/1,187.25
  6. Step 6: Final answer
    x = 951.98

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1.5x scale

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.