Answer:
A) 150
Step-by-step explanation:
All the angles in a triangle must add up to a total of 180 degrees.
So we can make an equation as given below:
20+10+?=180
30+?=180
?=150
So the missing angle is 150 degrees
The expression that is not a variation of the Pythagorean identity is the third option.
<h3>
What is the Pythagorean identity?</h3>
The Pythagorean identity can be written as:

For example, if we subtract cos^2(x) on both sides we get the second option:

Which is a variation.
Now, let's divide both sides by cos^2(x).

Notice that the third expression in the options looks like this one, but the one on the right side is positive. The above expression is in did a variation of the Pythagorean identity, then the one written in the options (with the 1 instead of the -1) is incorrect, meaning that it is not a variation of the Pythagorean identity.
Concluding, the correct option is the third one.
If you want to learn more about the Pythagorean identity, you can read:
brainly.com/question/24287773
Answer:
Height of the object is 68.6 cm.
Step-by-step explanation:
The height of the object can be determined by:
= 
From the given question;
object distance from pinhole = 3.6 m = 360 cm
image distance from pinhole = 4.2 cm
height of image = 0.8 cm
So that;
= 
⇒ object height = 
= 
= 68.571
object height = 68.6 cm
Thus, the height of the object is 68.6 cm.
Answer:
x = 2
Step-by-step explanation:
Answer:
x = 3/2 or 1.5
Step-by-step explanation:
6 - 2x = 3
(You have to subtract 6 on both sides so it can cancel out)
6 - 6 - 2x = 3 - 6
-2x = -3
(Now, you divide -2 on both sides to isolate the x)
-2/(-2)x = -3/(-2)
x = 3/2