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Finding the Fourth Proportional to 870.21, 1,310.49 and 784.55

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Solution

The fourth proportional to 870.21, 1,310.49 and 784.55 is: 1,181.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.21 : 1,310.49 = 784.55 : x
  2. Step 2: Convert to fraction form
    870.21/1,310.49 = 784.55/x
  3. Step 3: Cross multiply
    870.21x = 1,310.49 × 784.55
  4. Step 4: Simplify right side
    870.21x = 1,028,144.93
  5. Step 5: Solve for x
    x = 1,028,144.93/870.21
  6. Step 6: Final answer
    x = 1,181.49

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.