Answer:
x=70
Step-by-step explanation:
Angle 1 will be 90° when it subtends a 180° arc. That means the sum of 100° and (x+10) must be 180°, so (x+10) = 80°.
We assume this is intended to mean ...
... (x +10)° = 80° . . . . . note the ° symbol added outside parentheses
... x +10 = 80 . . . . . divide by °
... x = 70 . . . . . . . . .subtract 10
_____
If the intent is (x+10°) = 80°, then x=70°.
_____
<em>Comment on the numbers here</em>
Units need to be properly specified in problems of this nature. <em>As written</em>, we probably should assume that 10 is <em>radians</em>, and x is a large negative number, about -8.60374 (radians), or -492.958°.
A number of radians is a "pure number." It has <em>no units</em>. The term "radians" is used to signify that the number is considered to be an angle measure.
The answer is 11.25 mm.
A diameter of a circle is twice of its radius: d = 2r ⇒ r = d/2
small circle large circle
radius: r1 radius: r2 = ?
diameter: d1 = 15 mm
⇒ r1 = d1/2 = 15/2 mm
Since t<span>he ratio of the radii of two circles is 2:3, we have:
r1 : r2 = 2 : 3
which can also be expressed as:
</span>

<span>
We know that r1 is 7.5, so let's implement it:
</span>

Let's multiply both sides of the by 3r2:

⇒

⇒
Answer: Yes. When you solve your equations, you're solutions will change a little bit. It's good because it'll give you the right answer.
I hope this helps you and I hope it's right. ☺
There are 3 interior angles.