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Finding the Fourth Proportional to 1,378.39, 2,065.75 and 646.42

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Solution

The fourth proportional to 1,378.39, 2,065.75 and 646.42 is: 968.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.39 : 2,065.75 = 646.42 : x
  2. Step 2: Convert to fraction form
    1,378.39/2,065.75 = 646.42/x
  3. Step 3: Cross multiply
    1,378.39x = 2,065.75 × 646.42
  4. Step 4: Simplify right side
    1,378.39x = 1,335,342.12
  5. Step 5: Solve for x
    x = 1,335,342.12/1,378.39
  6. Step 6: Final answer
    x = 968.77

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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.