Home / 130.80-180.52-128.40

Finding the Fourth Proportional to 130.80, 180.52 and 128.40

Calculator

Solution

The fourth proportional to 130.80, 180.52 and 128.40 is: 177.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    130.80 : 180.52 = 128.40 : x
  2. Step 2: Convert to fraction form
    130.80/180.52 = 128.40/x
  3. Step 3: Cross multiply
    130.80x = 180.52 × 128.40
  4. Step 4: Simplify right side
    130.80x = 23,178.77
  5. Step 5: Solve for x
    x = 23,178.77/130.80
  6. Step 6: Final answer
    x = 177.21

Related Problems

Find fourth proportional to 65.40, 90.26 and 64.20
Half scale
Find fourth proportional to 261.60, 361.04 and 256.80
Double scale
Find fourth proportional to 131.80, 181.90 and 129.40
Similar ratio
Find fourth proportional to 196.20, 270.78 and 192.60
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.