<u>Let's take this problem step-by-step</u>:
<u>The ;unlabeled angle' adjacent to the 'outside angle of measure 78°'</u>
⇒ is on a straight line
⇒ sum of angle measure = 180 degrees

<u>Now we know:</u>
⇒ sum of all angles in a triangle ⇒ 180°
<u>Let's put that in equation form and solve:</u>

<u>Answer: 21°</u>
<u></u>
Hope that helps!
#LearnwithBrainly
Answer:
Step-by-step explanation:
Hint: 1- 2sin²x = Cos 2x
LHS = 1 - 2Sin² (π/4 - Ф/2)
= Cos 2 *(π/4 - Ф/2)
= Cos 2*π/4 - 2*Ф/2
= Cos π/2 - Ф
= Sin Ф = RHS
Answer:
5
Step-by-step explanation:
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