Answer:
The desired missing angle is 43⁰.
Step-by-step explanation:
Ans.
=> Let the missing angle be 'x'.
Then,
59⁰+78⁰+'x' = 180⁰ [:: the sum of interior angles of triangle is always 180⁰]
or,137⁰+'x'=180⁰
or 'x' = 180⁰-137⁰[the position 137 is now negative while performing in another equation]
HENCE,'x'=43⁰