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Finding the Fourth Proportional to 1,218.84, 1,681.68 and 721.48

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Solution

The fourth proportional to 1,218.84, 1,681.68 and 721.48 is: 995.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,218.84 : 1,681.68 = 721.48 : x
  2. Step 2: Convert to fraction form
    1,218.84/1,681.68 = 721.48/x
  3. Step 3: Cross multiply
    1,218.84x = 1,681.68 × 721.48
  4. Step 4: Simplify right side
    1,218.84x = 1,213,298.49
  5. Step 5: Solve for x
    x = 1,213,298.49/1,218.84
  6. Step 6: Final answer
    x = 995.45

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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.