Home / 1,120.05-1,680.57-390.15

Finding the Fourth Proportional to 1,120.05, 1,680.57 and 390.15

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Solution

The fourth proportional to 1,120.05, 1,680.57 and 390.15 is: 585.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,120.05 : 1,680.57 = 390.15 : x
  2. Step 2: Convert to fraction form
    1,120.05/1,680.57 = 390.15/x
  3. Step 3: Cross multiply
    1,120.05x = 1,680.57 × 390.15
  4. Step 4: Simplify right side
    1,120.05x = 655,674.39
  5. Step 5: Solve for x
    x = 655,674.39/1,120.05
  6. Step 6: Final answer
    x = 585.40

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Double scale
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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.