Home / 90.20-135.32-54.11

Finding the Fourth Proportional to 90.20, 135.32 and 54.11

Calculator

Solution

The fourth proportional to 90.20, 135.32 and 54.11 is: 81.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.20 : 135.32 = 54.11 : x
  2. Step 2: Convert to fraction form
    90.20/135.32 = 54.11/x
  3. Step 3: Cross multiply
    90.20x = 135.32 × 54.11
  4. Step 4: Simplify right side
    90.20x = 7,321.22
  5. Step 5: Solve for x
    x = 7,321.22/90.20
  6. Step 6: Final answer
    x = 81.17

Related Problems

Find fourth proportional to 45.10, 67.66 and 27.05
Half scale
Find fourth proportional to 180.39, 270.63 and 108.21
Double scale
Find fourth proportional to 91.20, 136.82 and 55.11
Similar ratio
Find fourth proportional to 135.29, 202.97 and 81.16
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.