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Finding the Fourth Proportional to 1,431.78, 1,975.80 and 810.78

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Solution

The fourth proportional to 1,431.78, 1,975.80 and 810.78 is: 1,118.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,431.78 : 1,975.80 = 810.78 : x
  2. Step 2: Convert to fraction form
    1,431.78/1,975.80 = 810.78/x
  3. Step 3: Cross multiply
    1,431.78x = 1,975.80 × 810.78
  4. Step 4: Simplify right side
    1,431.78x = 1,601,939.12
  5. Step 5: Solve for x
    x = 1,601,939.12/1,431.78
  6. Step 6: Final answer
    x = 1,118.84

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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.