Answer :

Solution:

Question 3:

The image below gives a vivid explanation of the question

Concept:

The sum of angles in a triangle is

[tex]=180^0[/tex][tex]\begin{gathered} \angle A+\angle B+\angle C=180^0 \\ \angle A=61^0 \\ \angle B=90^0 \\ \angle C=4f+1 \end{gathered}[/tex]

By substituting the values, we will have

[tex]\begin{gathered} \angle A+\angle B+\angle C=180^0 \\ 61^0+90^0+4f+1=180^0 \\ \text{collect similar terms, we will have} \\ 61+90+1+4f=180^0 \\ 152^0+4f=180^0 \\ 4f=180-152^0 \\ 4f=28^0 \\ \text{Divide both sides by 4} \\ \frac{4f}{4}=\frac{28}{4} \\ f=7^0 \end{gathered}[/tex]

Hence,

The final answer is f = 7°

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