Home / 171.64-256.92-139.78

Finding the Fourth Proportional to 171.64, 256.92 and 139.78

Calculator

Solution

The fourth proportional to 171.64, 256.92 and 139.78 is: 209.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    171.64 : 256.92 = 139.78 : x
  2. Step 2: Convert to fraction form
    171.64/256.92 = 139.78/x
  3. Step 3: Cross multiply
    171.64x = 256.92 × 139.78
  4. Step 4: Simplify right side
    171.64x = 35,912.28
  5. Step 5: Solve for x
    x = 35,912.28/171.64
  6. Step 6: Final answer
    x = 209.23

Related Problems

Find fourth proportional to 85.82, 128.46 and 69.89
Half scale
Find fourth proportional to 343.28, 513.84 and 279.56
Double scale
Find fourth proportional to 172.64, 258.42 and 140.78
Similar ratio
Find fourth proportional to 257.46, 385.38 and 209.67
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.