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Finding the Fourth Proportional to 870.51, 1,305.75 and 212.39

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Solution

The fourth proportional to 870.51, 1,305.75 and 212.39 is: 318.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.51 : 1,305.75 = 212.39 : x
  2. Step 2: Convert to fraction form
    870.51/1,305.75 = 212.39/x
  3. Step 3: Cross multiply
    870.51x = 1,305.75 × 212.39
  4. Step 4: Simplify right side
    870.51x = 277,328.66
  5. Step 5: Solve for x
    x = 277,328.66/870.51
  6. Step 6: Final answer
    x = 318.58

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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.