What is the measure of the missing angle

60°

Step-by-step explanation:

Two important rules to know

→ Angles in a triangle add up to 180°

→ Angles on a straight line add up to 180°

Since we have a triangle on the left we can work out the angle using fact 1 which is angles in a triangle add up to 180°. So,

x + 35 + 25 = 180

In an equation our aim is to find the value of what we are looking for as well as keeping the equation balanced. For example if we took away 60 only from one side then the equation would change so it's an important rule to keep in mind when solving equations, that you need to keep both sides of the equation the same.

x + 25 + 35 = 180

→ Simplify

x + 60 = 180

→ Minus 60 from both sides to isolate x

x = 120°

Now we can use fact 2 which was angles on a straight line add up to 180° to work out the '?'

x + 120 = 180

In an equation our aim is to find the value of what we are looking for as well as keeping the equation balanced. For example if we took away 120 only from one side then the equation would change so it's an important rule to keep in mind when solving equations, that you need to keep both sides of the equation the same.

x + 120 = 180

→ Minus 120 from both sides to isolate x

x = 60

Now we can again use fact 1 which was angles in a triangle add up to 180° to work out the '?'

60 + 60 + ? = 180

In an equation our aim is to find the value of what we are looking for as well as keeping the equation balanced. For example if we took away 120 only from one side then the equation would change so it's an important rule to keep in mind when solving equations, that you need to keep both sides of the equation the same.

60 + 60 + ? = 180

→ Simplify

120 + ? = 180

→ Minus 120 from both sides to isolate '?'

? = 60

c. 4 1/4 pounds