Home / 126.90-189.87-86.12

Finding the Fourth Proportional to 126.90, 189.87 and 86.12

Calculator

Solution

The fourth proportional to 126.90, 189.87 and 86.12 is: 128.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    126.90 : 189.87 = 86.12 : x
  2. Step 2: Convert to fraction form
    126.90/189.87 = 86.12/x
  3. Step 3: Cross multiply
    126.90x = 189.87 × 86.12
  4. Step 4: Simplify right side
    126.90x = 16,351.60
  5. Step 5: Solve for x
    x = 16,351.60/126.90
  6. Step 6: Final answer
    x = 128.85

Related Problems

Find fourth proportional to 63.45, 94.94 and 43.06
Half scale
Find fourth proportional to 253.80, 379.74 and 172.24
Double scale
Find fourth proportional to 127.90, 191.37 and 87.12
Similar ratio
Find fourth proportional to 190.35, 284.81 and 129.18
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.