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Finding the Fourth Proportional to 1,287.51, 1,776.88 and 728.08

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Solution

The fourth proportional to 1,287.51, 1,776.88 and 728.08 is: 1,004.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.51 : 1,776.88 = 728.08 : x
  2. Step 2: Convert to fraction form
    1,287.51/1,776.88 = 728.08/x
  3. Step 3: Cross multiply
    1,287.51x = 1,776.88 × 728.08
  4. Step 4: Simplify right side
    1,287.51x = 1,293,717.25
  5. Step 5: Solve for x
    x = 1,293,717.25/1,287.51
  6. Step 6: Final answer
    x = 1,004.82

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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.