Respuesta :

jennie51

Answer:

60⁰

Step-by-step explanation:

A triangle has three angles.

The sum of its angles = 180⁰

[ By angle sum property ]

Let the unknown angle be 'x'

Then,

30⁰ + 90⁰ + x = 180⁰

120⁰ + x = 180⁰

x = 180⁰ - 120⁰

x = 60⁰

Therefore, the unknown angle will be equal to 60⁰
60° because 90°+ 30°= 120°and 180°-120°=60°