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Finding the Fourth Proportional to 879.32, 1,212.72 and 646.40

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Solution

The fourth proportional to 879.32, 1,212.72 and 646.40 is: 891.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    879.32 : 1,212.72 = 646.40 : x
  2. Step 2: Convert to fraction form
    879.32/1,212.72 = 646.40/x
  3. Step 3: Cross multiply
    879.32x = 1,212.72 × 646.40
  4. Step 4: Simplify right side
    879.32x = 783,902.21
  5. Step 5: Solve for x
    x = 783,902.21/879.32
  6. Step 6: Final answer
    x = 891.49

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.