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Finding the Fourth Proportional to 858.49, 1,289.25 and 639.18

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Solution

The fourth proportional to 858.49, 1,289.25 and 639.18 is: 959.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.49 : 1,289.25 = 639.18 : x
  2. Step 2: Convert to fraction form
    858.49/1,289.25 = 639.18/x
  3. Step 3: Cross multiply
    858.49x = 1,289.25 × 639.18
  4. Step 4: Simplify right side
    858.49x = 824,062.82
  5. Step 5: Solve for x
    x = 824,062.82/858.49
  6. Step 6: Final answer
    x = 959.90

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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.