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Finding the Fourth Proportional to 817.35, 1,128.11 and 485.72

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Solution

The fourth proportional to 817.35, 1,128.11 and 485.72 is: 670.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.35 : 1,128.11 = 485.72 : x
  2. Step 2: Convert to fraction form
    817.35/1,128.11 = 485.72/x
  3. Step 3: Cross multiply
    817.35x = 1,128.11 × 485.72
  4. Step 4: Simplify right side
    817.35x = 547,941.16
  5. Step 5: Solve for x
    x = 547,941.16/817.35
  6. Step 6: Final answer
    x = 670.38

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Double scale
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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.