Home / 310.65-428.78-205.70

Finding the Fourth Proportional to 310.65, 428.78 and 205.70

Calculator

Solution

The fourth proportional to 310.65, 428.78 and 205.70 is: 283.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    310.65 : 428.78 = 205.70 : x
  2. Step 2: Convert to fraction form
    310.65/428.78 = 205.70/x
  3. Step 3: Cross multiply
    310.65x = 428.78 × 205.70
  4. Step 4: Simplify right side
    310.65x = 88,196.87
  5. Step 5: Solve for x
    x = 88,196.87/310.65
  6. Step 6: Final answer
    x = 283.91

Related Problems

Find fourth proportional to 155.33, 214.39 and 102.85
Half scale
Find fourth proportional to 621.30, 857.55 and 411.39
Double scale
Find fourth proportional to 311.65, 430.16 and 206.70
Similar ratio
Find fourth proportional to 465.98, 643.16 and 308.54
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.