Answer:
1st picture: d. 45.7°
2nd picture: b. 6, 7, 8
3rd picture: c. 342 m.
Explanation:
1st picture:
Given:
In right angled triangle
Base=7.8
Opposite= 8
x=?
we have



x=45.7°
Therefore, answer is d. 45.7°

2nd Picture:
Note:
The Pythagorean theorem states that in a right triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides.
longest side is hypotenuse.
let's check a. 3,4,5

25=25
It is a right angled triangle.
let's check b. 6,7,8
8^2=6^2+7^2
64≠85
Since the left-hand side of the equation is not equal to the right-hand side, we can conclude that the triangle is not a right angled triangle.
Therefore, the only option that does not make a right angle triangle
is b. 6, 7, 8

3rd Picture:
Given:
m∡Q=20°
m∡S= 90°
hypotenuse= 1000 meter
RS=?
We have:


doing criss cross multiplication:
RS = sin20*1000
RS=342 m
so, the answer is c. 342 m.