Home / 205.11-307.68-81.68

Finding the Fourth Proportional to 205.11, 307.68 and 81.68

Calculator

Solution

The fourth proportional to 205.11, 307.68 and 81.68 is: 122.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    205.11 : 307.68 = 81.68 : x
  2. Step 2: Convert to fraction form
    205.11/307.68 = 81.68/x
  3. Step 3: Cross multiply
    205.11x = 307.68 × 81.68
  4. Step 4: Simplify right side
    205.11x = 25,130.15
  5. Step 5: Solve for x
    x = 25,130.15/205.11
  6. Step 6: Final answer
    x = 122.52

Related Problems

Find fourth proportional to 102.55, 153.84 and 40.84
Half scale
Find fourth proportional to 410.21, 615.35 and 163.35
Double scale
Find fourth proportional to 206.11, 309.18 and 82.68
Similar ratio
Find fourth proportional to 307.66, 461.52 and 122.52
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.