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Finding the Fourth Proportional to 851.40, 1,278.45 and 646.20

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Solution

The fourth proportional to 851.40, 1,278.45 and 646.20 is: 970.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    851.40 : 1,278.45 = 646.20 : x
  2. Step 2: Convert to fraction form
    851.40/1,278.45 = 646.20/x
  3. Step 3: Cross multiply
    851.40x = 1,278.45 × 646.20
  4. Step 4: Simplify right side
    851.40x = 826,134.39
  5. Step 5: Solve for x
    x = 826,134.39/851.40
  6. Step 6: Final answer
    x = 970.32

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Double scale
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1.5x scale

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.