Home / 900-1,350-387

Finding the Fourth Proportional to 900, 1,350 and 387

Calculator

Solution

The fourth proportional to 900, 1,350 and 387 is: 580.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    900 : 1,350 = 387 : x
  2. Step 2: Convert to fraction form
    900/1,350 = 387/x
  3. Step 3: Cross multiply
    900x = 1,350 × 387
  4. Step 4: Simplify right side
    900x = 522,450
  5. Step 5: Solve for x
    x = 522,450/900
  6. Step 6: Final answer
    x = 580.50

Related Problems

Find fourth proportional to 450, 675 and 193.50
Half scale
Find fourth proportional to 1,800, 2,700 and 774
Double scale
Find fourth proportional to 901, 1,351.50 and 388
Similar ratio
Find fourth proportional to 1,350, 2,025 and 580.50
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.