The top corner of the triangle is 50°

The left corner of the triangle is 70°
Right corner is c
The right corner on the outside is d
Find d in the figure

1 answer

To find the angle \( d \) in the figure you described, we first need to find angle \( c \) of the triangle.

In a triangle, the sum of the interior angles always adds up to 180°. You have provided two angles:

  • Angle at the top corner = \( 50° \)
  • Angle at the left corner = \( 70° \)

Let’s calculate angle \( c \):

\[ c = 180° - (50° + 70°) \] \[ c = 180° - 120° \] \[ c = 60° \]

Now that we know angle \( c = 60° \), we can focus on finding angle \( d \).

Since angle \( d \) is located outside the triangle and is supplementary to angle \( c \), we can use the property that an exterior angle is equal to the sum of the two non-adjacent interior angles. In this case, angle \( d \) is formed by angle \( c \) and the angle at the top corner (50°).

Therefore, \( d \) can be found using the following relationship:

\[ d = 180° - c \] \[ d = 180° - 60° \] \[ d = 120° \]

So, the value of angle \( d \) is \( 120° \).