Home / 127.20-190.80-109.20

Finding the Fourth Proportional to 127.20, 190.80 and 109.20

Calculator

Solution

The fourth proportional to 127.20, 190.80 and 109.20 is: 163.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    127.20 : 190.80 = 109.20 : x
  2. Step 2: Convert to fraction form
    127.20/190.80 = 109.20/x
  3. Step 3: Cross multiply
    127.20x = 190.80 × 109.20
  4. Step 4: Simplify right side
    127.20x = 20,835.36
  5. Step 5: Solve for x
    x = 20,835.36/127.20
  6. Step 6: Final answer
    x = 163.80

Related Problems

Find fourth proportional to 63.60, 95.40 and 54.60
Half scale
Find fourth proportional to 254.40, 381.60 and 218.40
Double scale
Find fourth proportional to 128.20, 192.30 and 110.20
Similar ratio
Find fourth proportional to 190.80, 286.20 and 163.80
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.