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Finding the Fourth Proportional to 1,421.09, 2,131.62 and 641.45

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Solution

The fourth proportional to 1,421.09, 2,131.62 and 641.45 is: 962.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,421.09 : 2,131.62 = 641.45 : x
  2. Step 2: Convert to fraction form
    1,421.09/2,131.62 = 641.45/x
  3. Step 3: Cross multiply
    1,421.09x = 2,131.62 × 641.45
  4. Step 4: Simplify right side
    1,421.09x = 1,367,316.99
  5. Step 5: Solve for x
    x = 1,367,316.99/1,421.09
  6. Step 6: Final answer
    x = 962.16

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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.