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Finding the Fourth Proportional to 919.08, 1,378.61 and 646.39

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Solution

The fourth proportional to 919.08, 1,378.61 and 646.39 is: 969.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.08 : 1,378.61 = 646.39 : x
  2. Step 2: Convert to fraction form
    919.08/1,378.61 = 646.39/x
  3. Step 3: Cross multiply
    919.08x = 1,378.61 × 646.39
  4. Step 4: Simplify right side
    919.08x = 891,117.89
  5. Step 5: Solve for x
    x = 891,117.89/919.08
  6. Step 6: Final answer
    x = 969.58

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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.