Home / 1,121.02-1,681.10-390.40

Finding the Fourth Proportional to 1,121.02, 1,681.10 and 390.40

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Solution

The fourth proportional to 1,121.02, 1,681.10 and 390.40 is: 585.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,121.02 : 1,681.10 = 390.40 : x
  2. Step 2: Convert to fraction form
    1,121.02/1,681.10 = 390.40/x
  3. Step 3: Cross multiply
    1,121.02x = 1,681.10 × 390.40
  4. Step 4: Simplify right side
    1,121.02x = 656,301.44
  5. Step 5: Solve for x
    x = 656,301.44/1,121.02
  6. Step 6: Final answer
    x = 585.45

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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.