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Finding the Fourth Proportional to 1,281.27, 1,921.35 and 870.51

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Solution

The fourth proportional to 1,281.27, 1,921.35 and 870.51 is: 1,305.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,281.27 : 1,921.35 = 870.51 : x
  2. Step 2: Convert to fraction form
    1,281.27/1,921.35 = 870.51/x
  3. Step 3: Cross multiply
    1,281.27x = 1,921.35 × 870.51
  4. Step 4: Simplify right side
    1,281.27x = 1,672,554.39
  5. Step 5: Solve for x
    x = 1,672,554.39/1,281.27
  6. Step 6: Final answer
    x = 1,305.39

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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.