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Finding the Fourth Proportional to 870.39, 1,201.28 and 521.28

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Solution

The fourth proportional to 870.39, 1,201.28 and 521.28 is: 719.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.39 : 1,201.28 = 521.28 : x
  2. Step 2: Convert to fraction form
    870.39/1,201.28 = 521.28/x
  3. Step 3: Cross multiply
    870.39x = 1,201.28 × 521.28
  4. Step 4: Simplify right side
    870.39x = 626,198.54
  5. Step 5: Solve for x
    x = 626,198.54/870.39
  6. Step 6: Final answer
    x = 719.45

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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.