Home / 787.14-1,178.19-420.81

Finding the Fourth Proportional to 787.14, 1,178.19 and 420.81

Calculator

Solution

The fourth proportional to 787.14, 1,178.19 and 420.81 is: 629.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.14 : 1,178.19 = 420.81 : x
  2. Step 2: Convert to fraction form
    787.14/1,178.19 = 420.81/x
  3. Step 3: Cross multiply
    787.14x = 1,178.19 × 420.81
  4. Step 4: Simplify right side
    787.14x = 495,794.13
  5. Step 5: Solve for x
    x = 495,794.13/787.14
  6. Step 6: Final answer
    x = 629.87

Related Problems

Find fourth proportional to 393.57, 589.10 and 210.41
Half scale
Find fourth proportional to 1,574.28, 2,356.38 and 841.62
Double scale
Find fourth proportional to 788.14, 1,179.69 and 421.81
Similar ratio
Find fourth proportional to 1,180.71, 1,767.29 and 631.22
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.