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Finding the Fourth Proportional to 1,281.15, 1,921.71 and 511.65

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Solution

The fourth proportional to 1,281.15, 1,921.71 and 511.65 is: 767.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,281.15 : 1,921.71 = 511.65 : x
  2. Step 2: Convert to fraction form
    1,281.15/1,921.71 = 511.65/x
  3. Step 3: Cross multiply
    1,281.15x = 1,921.71 × 511.65
  4. Step 4: Simplify right side
    1,281.15x = 983,242.92
  5. Step 5: Solve for x
    x = 983,242.92/1,281.15
  6. Step 6: Final answer
    x = 767.47

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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.