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Finding the Fourth Proportional to 840.89, 1,160.25 and 491.42

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Solution

The fourth proportional to 840.89, 1,160.25 and 491.42 is: 678.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.89 : 1,160.25 = 491.42 : x
  2. Step 2: Convert to fraction form
    840.89/1,160.25 = 491.42/x
  3. Step 3: Cross multiply
    840.89x = 1,160.25 × 491.42
  4. Step 4: Simplify right side
    840.89x = 570,170.06
  5. Step 5: Solve for x
    x = 570,170.06/840.89
  6. Step 6: Final answer
    x = 678.06

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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.