Home / 1,138.12-1,570.40-640.72

Finding the Fourth Proportional to 1,138.12, 1,570.40 and 640.72

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Solution

The fourth proportional to 1,138.12, 1,570.40 and 640.72 is: 884.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.12 : 1,570.40 = 640.72 : x
  2. Step 2: Convert to fraction form
    1,138.12/1,570.40 = 640.72/x
  3. Step 3: Cross multiply
    1,138.12x = 1,570.40 × 640.72
  4. Step 4: Simplify right side
    1,138.12x = 1,006,186.69
  5. Step 5: Solve for x
    x = 1,006,186.69/1,138.12
  6. Step 6: Final answer
    x = 884.08

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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.