Home / 490.57-676.98-280.78

Finding the Fourth Proportional to 490.57, 676.98 and 280.78

Calculator

Solution

The fourth proportional to 490.57, 676.98 and 280.78 is: 387.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    490.57 : 676.98 = 280.78 : x
  2. Step 2: Convert to fraction form
    490.57/676.98 = 280.78/x
  3. Step 3: Cross multiply
    490.57x = 676.98 × 280.78
  4. Step 4: Simplify right side
    490.57x = 190,082.44
  5. Step 5: Solve for x
    x = 190,082.44/490.57
  6. Step 6: Final answer
    x = 387.47

Related Problems

Find fourth proportional to 245.29, 338.49 and 140.39
Half scale
Find fourth proportional to 981.14, 1,353.96 and 561.56
Double scale
Find fourth proportional to 491.57, 678.36 and 281.78
Similar ratio
Find fourth proportional to 735.86, 1,015.47 and 421.17
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.