- 18 The diagram shows triangle PQR.
Diagram NOT
accurately drawn
P
17.8 cm
360
R
26.3 cm
Calculate the length of PR.
Give your answer correct to 3 significant figures.

The length of PR is 15.8 cm

Step-by-step explanation:

We will solve the question using the cosine rule

In ΔPQR

∵ (PR)² = (PQ)² + (RQ)² - 2(PQ)(RQ)(cos∠Q)

∵ PQ = 17.8 cm

∵ RQ = 26.3 cm

∵ m∠Q = 36°

→ Substitute them in the rule above

∵ (PR)² = (17.8)² + (26.3)² - 2(17.8)(26.3)(cos36)

∴ (PR)² = 316.84 + 691.69 - 936.28(cos36)

∴ (PR)² = 251.0635685

→ Take √ for both sides

∴ PR = 15.8449856

→ Correct it to 3 significant figures

∴ PR = 15.8 cm

∴ The length of PR is 15.8 cm

black/brown

step-by-step explanation:

well, you see here, jamal was born to 2 parents, his mother who he lives with and his father who left at a young age and who happens to be younger than him. he stole cookies because he has to steal food due to the fact that he spends his government poverty checks on pot and women.

let's add {f(x)=x+1}f(x)=x+1 and {g(x)=2x}g(x)=2x together to make a new function.

f(x)+g(x) =(x+1)+(2x)=x+1+2x=3x+1

let's call this new function hh. so we have:

{h(x)}={f(x)}+{g(x)}{=3x+1}h(x)=f(x)+g(x)=3x+1

we can also evaluate combined functions for particular inputs. let's evaluate function hh above for x=2x=2. below are two ways of doing this.

method 1: substitute x=2x=2 into the combined function hh.

h(x)

h(2)

​    

=3x+1

=3(2)+1

=7

​ since h(x)=f(x)+g(x)h(x)=f(x)+g(x), we can also find h(2)h(2) by finding f(2) +g(2)f(2)+g(2).

first, let's find f(2)f(2):

f(x)

f(2)

​    

=x+1

=2+1

=3

​  

now, let's find g(2)g(2):

g(x)

g(2)

​    

=2x

=2⋅2

=4

​  

so f(2)+g(2)=3+4=\greend7f(2)+g(2)=3+4=7.

notice that substituting x =2x=2 directly into function hh and finding f(2) + g(2)f(2)+g(2) gave us the same answer!