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Finding the Fourth Proportional to 818.50, 1,128.75 and 631.70

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Solution

The fourth proportional to 818.50, 1,128.75 and 631.70 is: 871.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.50 : 1,128.75 = 631.70 : x
  2. Step 2: Convert to fraction form
    818.50/1,128.75 = 631.70/x
  3. Step 3: Cross multiply
    818.50x = 1,128.75 × 631.70
  4. Step 4: Simplify right side
    818.50x = 713,031.38
  5. Step 5: Solve for x
    x = 713,031.38/818.50
  6. Step 6: Final answer
    x = 871.14

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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.