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Finding the Fourth Proportional to 985.52, 1,357.76 and 819.21

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Solution

The fourth proportional to 985.52, 1,357.76 and 819.21 is: 1,128.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    985.52 : 1,357.76 = 819.21 : x
  2. Step 2: Convert to fraction form
    985.52/1,357.76 = 819.21/x
  3. Step 3: Cross multiply
    985.52x = 1,357.76 × 819.21
  4. Step 4: Simplify right side
    985.52x = 1,112,297.71
  5. Step 5: Solve for x
    x = 1,112,297.71/985.52
  6. Step 6: Final answer
    x = 1,128.64

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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.