Trigonometric Functions: specifically area of minor segments (1 Viewer)

[trib_j]

The question is "The dartboard above has a radius of 23 cm. The shaded area has a height of 7mm. If a player must hit the shaded area to win, find:
a) The area of the shaded part, to the nearest square centimetre
The answer is 5cm^2, but I don't know how to get there. Please halp

*If people use the Maths in Focus Textbooks it's in exercise 5.5, q12a

 

[integral95]

Lol i would need to see a diagram as i need to figure out the angle it subtends.

I'm guessing you would have to use the formula

and i'm worked out that with the answer given

Edit: how does it involve trig functions lol