In an equilateral triangle PQR, the side QR is trisected at S. Prove that 9PS square
= 7PQ square
Answers
Answer:
REFER IN ATTACHMENT
MARK AS BRAINLIST ANSWER
Given :- In an equilateral triangle PQR, the side QR is trisected at S.
To Prove :- 9•PS² = 7•PQ² .
Formula used :-
- Altitude of an equilateral triangle = (√3/2) × side .
- Altitude of an equilateral triangle bisect the base .
- Pythagoras theorem :- (Perpendicular)² + (Base)² = (Hypotenuse)²
Solution :-
Let us assume that, each side of the given equilateral triangle PQR is equal to a unit and let PT is the altitude .
So,
→ PT = (√3a/2) unit { Altitude = (√3/2)•side } ------- Equation (1)
→ QT = TR = QR/2 = (a/2) unit { since altitude bisect the base }
Now, we have given that, QR is trisected as S .
So,
→ QS = (1/3)•QR
→ QS = (a/3) unit
then,
→ ST = QT - QS
putting values from above in RHS,
→ ST = (a/2) - (a/3)
→ ST = (3a - 2a)/6
→ ST = (a/6) unit -------- Equation (2)
Now, in right angled ∆PTS we have,
→ PS² = PT² + ST²
putting values from Equation (1) and Equation (2) in RHS,
→ PS² = (√3a/2)² + (a/6)²
→ PS² =(3a²/4) + (a²/36)
→ PS² = (27a² + a²)/36
→ PS² = (28a²/36)
→ PS² = (7a²/9)
→ 9•PS² = 7a²
since each side of given equilateral triangle is equal to a unit, finally putting a = PQ in RHS,
→ 9•PS² = 7•PQ² (Proved)
Learn more :-
In the figure ∠ MNP = 90°, ∠ MQN = 90°, , MQ = 12 , QP = 3 then find NQ .
https://brainly.in/question/47411321
show that AB2 = AD.AC
https://brainly.in/question/47273910