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Finding the Fourth Proportional to 1,128.90, 1,693.14 and 398.39

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Solution

The fourth proportional to 1,128.90, 1,693.14 and 398.39 is: 597.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,128.90 : 1,693.14 = 398.39 : x
  2. Step 2: Convert to fraction form
    1,128.90/1,693.14 = 398.39/x
  3. Step 3: Cross multiply
    1,128.90x = 1,693.14 × 398.39
  4. Step 4: Simplify right side
    1,128.90x = 674,521.58
  5. Step 5: Solve for x
    x = 674,521.58/1,128.90
  6. Step 6: Final answer
    x = 597.50

Related Problems

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Half scale
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Double scale
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Similar ratio
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.