Home / 197.21-295.61-128.78

Finding the Fourth Proportional to 197.21, 295.61 and 128.78

Calculator

Solution

The fourth proportional to 197.21, 295.61 and 128.78 is: 193.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    197.21 : 295.61 = 128.78 : x
  2. Step 2: Convert to fraction form
    197.21/295.61 = 128.78/x
  3. Step 3: Cross multiply
    197.21x = 295.61 × 128.78
  4. Step 4: Simplify right side
    197.21x = 38,068.66
  5. Step 5: Solve for x
    x = 38,068.66/197.21
  6. Step 6: Final answer
    x = 193.04

Related Problems

Find fourth proportional to 98.61, 147.81 and 64.39
Half scale
Find fourth proportional to 394.42, 591.22 and 257.56
Double scale
Find fourth proportional to 198.21, 297.11 and 129.78
Similar ratio
Find fourth proportional to 295.82, 443.42 and 193.17
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.