How are the proofs the side length ratios of 30-60-90 and 45-45-90 triangles similar? how are they different?

Solution:

Consider the Triangle ABC in which , ∠A=60°, ∠B=90°,∠C=30°

Let , Perpendicular =  P

We will use trigonometric ratio to prove that ratio of sides  will always be same by using either of angles that is 30° or 60°.

Sin C=

Sin 30°=

So, Ratio of Perpendicular and Hypotenuse is always constant, that is always  .

Therefore , Hypotenuse will be = 2 P

Now, using Pythagoras Theorem

⇒(Perpendicular)² + (Base)² = (Hypotenuse)²

⇒P²+ (Base)²=(2 P)²

⇒ (Base)²= 4 P²- P²

⇒(Base)²= 3 P²

⇒ Base= √3 P

So, ratio of Perpendicular to Base or Base to Perpendicular is .

Sin 60°=

⇒If you consider either angle of 30° or 60° to find the side length ratios, , then also ratio of sides is always that is  BC: AB or BC: AC or AB: AC →→ AB : BC : AC = 1 : √3 : 2 .

now, consider Triangle P QR, in which ∠P=∠R= 45°,∠Q=90°

To find the side length ratio we will use trigonometric ratio.

→Tan 45°=

→1=

→P Q= QR

Let , P Q= QR= K

Using Pythagoras theorem

⇒(Perpendicular)² + (Base)² = (Hypotenuse)²

⇒ K² + K²= (Hypotenuse)²

⇒(Hypotenuse)²= 2 K²

Hypotenuse= √2 K

⇒If you consider either angle that is of 45°  to find the side length ratios, , then also ratio of sides is always that is  P Q: QR or P Q: PR or QR: PR →→ P Q : QR : PR = 1 : 1:√2.

-10i^2-4i

step-by-step explanation:

evaluate for p=2,q=5i

(2−4)(2+5i)i

(2−4)(2+5i)i

=−10i2−4i

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18