Please help!
Find the unknown angle measures
Options: 30°, 51.5°, 60°, 141.5°

Answer:51.5 degree
Step-by-step explanation: Since DEF is an isosceles triangle, angle D and F needs to be equal. So substract 77 from 180 and divide by 2.
Answer:
Step-by-step explanation:
let angle D and angle F be x
x+x+77=180 degree(being sum of the interior angle of a triangle)
2x=180-77
x=103/2
x=51.2 degree
both angle D and F are 51.2 degree because the base angles of an isosceles triangle are equal.