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Finding the Fourth Proportional to 817.40, 1,128.06 and 485.84

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Solution

The fourth proportional to 817.40, 1,128.06 and 485.84 is: 670.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.40 : 1,128.06 = 485.84 : x
  2. Step 2: Convert to fraction form
    817.40/1,128.06 = 485.84/x
  3. Step 3: Cross multiply
    817.40x = 1,128.06 × 485.84
  4. Step 4: Simplify right side
    817.40x = 548,056.67
  5. Step 5: Solve for x
    x = 548,056.67/817.40
  6. Step 6: Final answer
    x = 670.49

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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.