Home / 286.20-429.28-80.78

Finding the Fourth Proportional to 286.20, 429.28 and 80.78

Calculator

Solution

The fourth proportional to 286.20, 429.28 and 80.78 is: 121.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    286.20 : 429.28 = 80.78 : x
  2. Step 2: Convert to fraction form
    286.20/429.28 = 80.78/x
  3. Step 3: Cross multiply
    286.20x = 429.28 × 80.78
  4. Step 4: Simplify right side
    286.20x = 34,674.89
  5. Step 5: Solve for x
    x = 34,674.89/286.20
  6. Step 6: Final answer
    x = 121.16

Related Problems

Find fourth proportional to 143.10, 214.64 and 40.39
Half scale
Find fourth proportional to 572.40, 858.56 and 161.55
Double scale
Find fourth proportional to 287.20, 430.78 and 81.78
Similar ratio
Find fourth proportional to 429.30, 643.92 and 121.16
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.