Home / 219.40-328.78-128.13

Finding the Fourth Proportional to 219.40, 328.78 and 128.13

Calculator

Solution

The fourth proportional to 219.40, 328.78 and 128.13 is: 192.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    219.40 : 328.78 = 128.13 : x
  2. Step 2: Convert to fraction form
    219.40/328.78 = 128.13/x
  3. Step 3: Cross multiply
    219.40x = 328.78 × 128.13
  4. Step 4: Simplify right side
    219.40x = 42,126.58
  5. Step 5: Solve for x
    x = 42,126.58/219.40
  6. Step 6: Final answer
    x = 192.01

Related Problems

Find fourth proportional to 109.70, 164.39 and 64.07
Half scale
Find fourth proportional to 438.80, 657.56 and 256.26
Double scale
Find fourth proportional to 220.40, 330.28 and 129.13
Similar ratio
Find fourth proportional to 329.10, 493.17 and 192.20
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.