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Finding the Fourth Proportional to 1,189.58, 1,783.60 and 642.15

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Solution

The fourth proportional to 1,189.58, 1,783.60 and 642.15 is: 962.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,189.58 : 1,783.60 = 642.15 : x
  2. Step 2: Convert to fraction form
    1,189.58/1,783.60 = 642.15/x
  3. Step 3: Cross multiply
    1,189.58x = 1,783.60 × 642.15
  4. Step 4: Simplify right side
    1,189.58x = 1,145,338.74
  5. Step 5: Solve for x
    x = 1,145,338.74/1,189.58
  6. Step 6: Final answer
    x = 962.81

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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.