angle for triangle is 180°
angle ACB is 75° because it has mention that is an isosceles triangle
So that angle of BAC is 180°-75°-75°=30°
The area of the shaded region is
.
Solution:
Given radius = 4 cm
Diameter = 2 × 4 = 8 cm
Let us first find the area of the semi-circle.
Area of the semi-circle = 


Area of the semi-circle =
cm²
Angle in a semi-circle is always 90º.
∠C = 90°
So, ABC is a right angled triangle.
Using Pythagoras theorem, we can find base of the triangle.




cm
Base of the triangle ABC =
cm
Height of the triangle = 4 cm
Area of the triangle ABC = 

Area of the triangle ABC =
cm²
Area of the shaded region
= Area of the semi-circle – Area of the triangle ABC
= 
= 
Hence the area of the shaded region is
.
First, 1950m=1.95km, as 1000m=1km.
Then, 2.5-1.95=0.55km
0.55km = 550m
Check the picture below, so pretty much reaches its maximum height at the vertex, now let's take a peek at the equation above hmmmm
![~~~~~~\textit{vertical parabola vertex form} \\\\ y=a(x- h)^2+ k\qquad \begin{cases} \stackrel{vertex}{(h,k)}\\\\ \stackrel{"a"~is~negative}{op ens~\cap}\qquad \stackrel{"a"~is~positive}{op ens~\cup} \end{cases} \\\\[-0.35em] ~\dotfill\\\\ h(t)=-16(t ~~ - ~~ \stackrel{h}{5})^2~~ + ~~\stackrel{k}{116}~\hfill \underset{maximum~height}{\stackrel{vertex}{(5~~,~~\underset{\uparrow }{116})}}](https://tex.z-dn.net/?f=~~~~~~%5Ctextit%7Bvertical%20parabola%20vertex%20form%7D%20%5C%5C%5C%5C%20y%3Da%28x-%20h%29%5E2%2B%20k%5Cqquad%20%5Cbegin%7Bcases%7D%20%5Cstackrel%7Bvertex%7D%7B%28h%2Ck%29%7D%5C%5C%5C%5C%20%5Cstackrel%7B%22a%22~is~negative%7D%7Bop%20ens~%5Ccap%7D%5Cqquad%20%5Cstackrel%7B%22a%22~is~positive%7D%7Bop%20ens~%5Ccup%7D%20%5Cend%7Bcases%7D%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill%5C%5C%5C%5C%20h%28t%29%3D-16%28t%20~~%20-%20~~%20%5Cstackrel%7Bh%7D%7B5%7D%29%5E2~~%20%2B%20~~%5Cstackrel%7Bk%7D%7B116%7D~%5Chfill%20%5Cunderset%7Bmaximum~height%7D%7B%5Cstackrel%7Bvertex%7D%7B%285~~%2C~~%5Cunderset%7B%5Cuparrow%20%7D%7B116%7D%29%7D%7D)
Its just simple subtract the p to 7p you will get 6p .