Home / 320.40-438.96-308.10

Finding the Fourth Proportional to 320.40, 438.96 and 308.10

Calculator

Solution

The fourth proportional to 320.40, 438.96 and 308.10 is: 422.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    320.40 : 438.96 = 308.10 : x
  2. Step 2: Convert to fraction form
    320.40/438.96 = 308.10/x
  3. Step 3: Cross multiply
    320.40x = 438.96 × 308.10
  4. Step 4: Simplify right side
    320.40x = 135,243.58
  5. Step 5: Solve for x
    x = 135,243.58/320.40
  6. Step 6: Final answer
    x = 422.11

Related Problems

Find fourth proportional to 160.20, 219.48 and 154.05
Half scale
Find fourth proportional to 640.80, 877.92 and 616.20
Double scale
Find fourth proportional to 321.40, 440.33 and 309.10
Similar ratio
Find fourth proportional to 480.60, 658.44 and 462.15
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.