The question is only answerable if you mean a regular 14-agon - otherwise they can be many values as long as the sum of all 14 angles is a constant.
There are two ways of calculating it:
1) Calculating sum of interior angles and divide by 14:
sum_interior_angles = (number_of_sides - 2) × 180°
interior_angle = sum_interior_angles ÷ number_of_sides
→ interior_angle = (14 - 2) × 180° ÷˙14 = 2160° ÷ 14 = 154 2/7 ≈ 154.3°
2) Find exterior angle and use fact that interior and exterior angles are supplementary
sum_exterior_angles = 360°
exterior_angle = 360° ÷ number_of_sides
→ exterior_angle = 360° ÷ 14 = 25 5/7° (≈ 25.7°)
interior_angle + exterior angle = 180°
→ interior_angle = 180° - exterior_angle
→ interior_angle = 180° - 360° ÷ 14 = 180° - 25 5/7° = 154 2/7° ≈ 154.3°
(The exterior angle 25 5/7° ≈ 25.7°)
interior_angle + exterior_angle = 180°
If the polygon is regular, the measure of one interior angle of a 24 side polygon is 165 degrees.
120
42
Interior angles total 2520 degrees
Providing that it's a regular polygon each interior angle is: 1520 18' 27.69''
The measure of each interior angle of a fifteen sided regular polygon, a pendedecagon, is 156o.
The interior angle of an octdecagon, an 18 sided regular polygon, is 160o.
Providing that it is a regular 38 sided polygon then each interior angle will measure: 170o31'34.74''
A 16 sided polygon
The interior angles of an 11 sided polygon add up to 1620 degrees
Providing that it is a regular polygon then each interior angle will measure 160 degrees
If the polygon is regular, the measure of one interior angle of a 24 side polygon is 165 degrees.
The interior angles of a 16 sided polygon add up to 2520 degrees If it's a regular polygon then each interior angle measures 157.5 degrees
120
42
51º per interior angle
The 13 interior angles of a 13 sided polygon add up to 1,980 degrees