Home / 180.78-249.28-128.31

Finding the Fourth Proportional to 180.78, 249.28 and 128.31

Calculator

Solution

The fourth proportional to 180.78, 249.28 and 128.31 is: 176.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    180.78 : 249.28 = 128.31 : x
  2. Step 2: Convert to fraction form
    180.78/249.28 = 128.31/x
  3. Step 3: Cross multiply
    180.78x = 249.28 × 128.31
  4. Step 4: Simplify right side
    180.78x = 31,985.12
  5. Step 5: Solve for x
    x = 31,985.12/180.78
  6. Step 6: Final answer
    x = 176.93

Related Problems

Find fourth proportional to 90.39, 124.64 and 64.16
Half scale
Find fourth proportional to 361.56, 498.56 and 256.62
Double scale
Find fourth proportional to 181.78, 250.66 and 129.31
Similar ratio
Find fourth proportional to 271.17, 373.92 and 192.47
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.