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Finding the Fourth Proportional to 1,218.06, 1,681.20 and 720.99

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Solution

The fourth proportional to 1,218.06, 1,681.20 and 720.99 is: 995.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,218.06 : 1,681.20 = 720.99 : x
  2. Step 2: Convert to fraction form
    1,218.06/1,681.20 = 720.99/x
  3. Step 3: Cross multiply
    1,218.06x = 1,681.20 × 720.99
  4. Step 4: Simplify right side
    1,218.06x = 1,212,128.39
  5. Step 5: Solve for x
    x = 1,212,128.39/1,218.06
  6. Step 6: Final answer
    x = 995.13

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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.