tell me 4 question.
Answers
Solution :-
1)
Given that tan θ = 8/15
On squaring both sides then
=> (tan θ)² = (8/15)²
=> tan² θ = 64/225
On adding 1 both sides then
=> tan² θ + 1 = (64/225)+1
=> tan² θ + 1 = (64+225)/225
=> tan² θ + 1 = 289/225
We know that
sec² θ - tan² θ = 1
=> sec² θ = 289/225
=> sec θ = √(289/225)
=> sec θ = 17/15
Therefore, sec θ = 17/15
2)
In ∆ PQR , ∠ PQR = 90°
QS ⊥ PR
QS = 12 cm
QS = 12 cmRS = 16 cm
We know that
∆PQS and ∆QSR and ∆ PQR are similar triangles
So , we know that
The square of the perpendicular drawn from the right angle to the hypotenuse is equal to the product of the two sides on the hypotenuse formed by the perpendicular.
Therefore, QS² = PS×SR
=> 12² = PS × 16
=> 144 = PS × 16
=> PS = 144/16
=> PS = 9 cm
Now,
We have ,
PR = PS + SR
=> PR = 9+16
Therefore, PR = 25 cm
The length of the side PR = 25 cm
3)
Given that
D lies on x-axis
We know that
The equation of x-axis is y = 0
So ,The ordinate of D = 0
The distance between D from y-axis
= 5 units
The distance from y-axis = abscissa = 5
The coordinates of D = (5,0)
4)
Given that
The ratio of two triangles with common base = 4:5
Let they be 4X cm² and 5X cm²
The area of the bigger triangle = 5X cm²
The area of the smaller triangle = 4X cm²
Given that
The base of two triangles are same
Let the base of the two triangles be b cm
Height of the smaller triangle = 6 cm
Now,
Area of the triangle = (1/2)×base×height sq.units
=> Area of the smaller triangle
=> (1/2)×b×6 = 4
=> 6b/2 = 4
=> 3×b = 4
=> b= 4/3 cm
Therefore, b = 4/3 cm
The length of the base = 4/3 cm
Area of the greater triangle = 5 cm²
=> (1/2)×(4/3)×h = 5
=> (4/6)×h = 5
=> (2/3)×h = 5
=> h = 5/(2/3)
=> h = 5×3/2
=> h = 15/2
=> h = 7.5 cm
Therefore, Height of the greater triangle is 7.5 cm
Step-by-step explanation:
Solution :-
1)
Given that tan θ = 8/15
On squaring both sides then
=> (tan θ)² = (8/15)²
=> tan² θ = 64/225
On adding 1 both sides then
=> tan² θ + 1 = (64/225)+1
=> tan² θ + 1 = (64+225)/225
=> tan² θ + 1 = 289/225
We know that
sec² θ - tan² θ = 1
=> sec² θ = 289/225
=> sec θ = √(289/225)
=> sec θ = 17/15
Therefore, sec θ = 17/15
2)
In ∆ PQR , ∠ PQR = 90°
QS ⊥ PR
QS = 12 cm
QS = 12 cmRS = 16 cm
We know that
∆PQS and ∆QSR and ∆ PQR are similar triangles
So , we know that
The square of the perpendicular drawn from the right angle to the hypotenuse is equal to the product of the two sides on the hypotenuse formed by the perpendicular.
Therefore, QS² = PS×SR
=> 12² = PS × 16
=> 144 = PS × 16
=> PS = 144/16
=> PS = 9 cm
Now,
We have ,
PR = PS + SR
=> PR = 9+16
Therefore, PR = 25 cm
The length of the side PR = 25 cm
3)
Given that
D lies on x-axis
We know that
The equation of x-axis is y = 0
So ,The ordinate of D = 0
The distance between D from y-axis
= 5 units
The distance from y-axis = abscissa = 5
The coordinates of D = (5,0)
4)
Given that
The ratio of two triangles with common base = 4:5
Let they be 4X cm² and 5X cm²
The area of the bigger triangle = 5X cm²
The area of the smaller triangle = 4X cm²
Given that
The base of two triangles are same
Let the base of the two triangles be b cm
Height of the smaller triangle = 6 cm
Now,
Area of the triangle = (1/2)×base×height sq.units
=> Area of the smaller triangle
=> (1/2)×b×6 = 4
=> 6b/2 = 4
=> 3×b = 4
=> b= 4/3 cm
Therefore, b = 4/3 cm
The length of the base = 4/3 cm
Area of the greater triangle = 5 cm²
=> (1/2)×(4/3)×h = 5
=> (4/6)×h = 5
=> (2/3)×h = 5
=> h = 5/(2/3)
=> h = 5×3/2
=> h = 15/2
=> h = 7.5 cm