Home / 200.40-300.50-78.71

Finding the Fourth Proportional to 200.40, 300.50 and 78.71

Calculator

Solution

The fourth proportional to 200.40, 300.50 and 78.71 is: 118.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    200.40 : 300.50 = 78.71 : x
  2. Step 2: Convert to fraction form
    200.40/300.50 = 78.71/x
  3. Step 3: Cross multiply
    200.40x = 300.50 × 78.71
  4. Step 4: Simplify right side
    200.40x = 23,650.46
  5. Step 5: Solve for x
    x = 23,650.46/200.40
  6. Step 6: Final answer
    x = 118.02

Related Problems

Find fourth proportional to 100.20, 150.25 and 39.35
Half scale
Find fourth proportional to 400.80, 600.99 and 157.41
Double scale
Find fourth proportional to 201.40, 301.99 and 79.71
Similar ratio
Find fourth proportional to 300.60, 450.74 and 118.06
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.