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Finding the Fourth Proportional to 818.78, 1,128.58 and 712.16

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Solution

The fourth proportional to 818.78, 1,128.58 and 712.16 is: 981.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.78 : 1,128.58 = 712.16 : x
  2. Step 2: Convert to fraction form
    818.78/1,128.58 = 712.16/x
  3. Step 3: Cross multiply
    818.78x = 1,128.58 × 712.16
  4. Step 4: Simplify right side
    818.78x = 803,730.35
  5. Step 5: Solve for x
    x = 803,730.35/818.78
  6. Step 6: Final answer
    x = 981.63

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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.