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Finding the Fourth Proportional to 855.78, 1,181.56 and 561.55

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Solution

The fourth proportional to 855.78, 1,181.56 and 561.55 is: 775.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    855.78 : 1,181.56 = 561.55 : x
  2. Step 2: Convert to fraction form
    855.78/1,181.56 = 561.55/x
  3. Step 3: Cross multiply
    855.78x = 1,181.56 × 561.55
  4. Step 4: Simplify right side
    855.78x = 663,506.14
  5. Step 5: Solve for x
    x = 663,506.14/855.78
  6. Step 6: Final answer
    x = 775.32

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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.