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3 years ago

Two tangents drawn to a circle from a point outside it, are equal in length.prove it.

1 answer:

7 0

Given: A circle with centre O; PA and PB are two tangents to the circle drawn from an external point P.
To prove: PA = PB
Construction: Join OA, OB, and OP.
It is known that a tangent at any point of a circle is perpendicular to the radius through the point of contact.
OA⊥PA
OB⊥PB
In △OPA and △OPB
∠OPA=∠OPB (Using (1))
OA=OB (Radii of the same circle)
OP=OP (Common side)
Therefor △OPA≅△OPB (RHS congruency criterion)
PA=PB
(Corresponding parts of congruent triangles are equal)
Thus, it is proved that the lengths of the two tangents drawn from an external point to a circle are equal.
The length of tangents drawn from any external point are equal.
So statement is correct

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Determine if the statement is true or false. If a linear system has the same number of equations and variables, then it must hav

lutik1710 [3]

Answer:

False

Step-by-step explanation:

Consider the equations with the same number of equations and variables as shown below,

Case 1

$x_{1} + x_{2} = 0\\x_{1} + x_{2} = 1$

This equation has no solution because it is not possible to have two numbers that give a sum of 0 and 1 simultaneously.

Case 2

$x_{1} + x_{2} = 1\\2x_{1} + 2x_{2} = 2$

This equation has infinitely many possible solutions.

Therefore it is FALSE to say a linear system with the same number of equations and variables, must have a unique solution.

5 0

3 years ago

The set of ordered pairs below represents a linear function.

vivado [14]

Answer:

(4,0)

Step-by-step explanation:

It is a linear function so you find the slope by doing y2-y1/x2-x1 and you find the slope to be 1/2. You can then setup an equation using it and graph it to find the next value.

7 0

3 years ago

Read 2 more answers

Given that tan θ ≈ −0.087, where 3 2 π < θ < 2 , π find the values of sin θ and cos θ.

elena-s [515]

Answer:

sin θ ≈ -0.08667
cos θ ≈ 0.99624

Step-by-step explanation:

Straightforward use of the inverse tangent function of a calculator will tell you θ ≈ -0.08678 radians. This is an angle in the 4th quadrant, where your restriction on θ places it. (To comply with the restriction, you would need to consider the angle value to be 2π-0.08678 radians. The trig values for this angle are the same as the trig values for -0.08678 radians.)

Likewise, straightforward use of the calculator to find the other function values gives ...

sin(-0.08678 radians) ≈ -0.08667

cos(-0.08678 radians) ≈ 0.99624

_____

Note on inverse tangent

Depending on the mode setting of your calculator, the arctan or tan⁻¹ function may give you a value in degrees, not radians. That doesn't matter for this problem. sin(arctan(-0.087)) is the same whether the angle is degrees or radians, as long as you don't change the mode in the middle of the computation.

We have shown radians in the above answer because the restriction on the angle is written in terms of radians.

_____

Alternate solution

The relationship between tan and sin and cos in the 4th quadrant is ...

$\cos{\theta}=\dfrac{1}{\sqrt{1+\tan^2{\theta}}}\\\\\sin{\theta}=\dfrac{\tan{\theta}}{\sqrt{1+\tan^2{\theta}}}$

That is, the cosine is positive, and the sign of the sine matches that of the tangent.

This more complicated computation gives the same result as above.

4 0

3 years ago

Write the equation of each line using the given information.

Marat540 [252]

A. The equation of the line is y = -0.2 x + 1.9

B. The equation of the line is y = 4 x + 3

C. The equation of the line is y = -8

D. The equation of the line is y = 2 x + 4

Step-by-step explanation:

The slope-intercept form of the equation of a line is y = m x + b, where

m is the slope of the line and b is the y-intercept

The formula of the slope of a line which passes through points $(x_{1},y_{1})$ and $(x_{2},y_{2})$ is $m=\frac{y_{2}-y_{1}}{x_{2}-x_{1}}$
The slope of a horizontal line whose equation y = b is zero
The y-intercept means the line intersect the y-axis at point (0 , b)

∵ The line passes through points (2 , 1.5) and (-5 , 36.5)

∴ $x_{1}$ = 2 and $x_{2}$ = -5

∴ $y_{1}$ = 1.5 and $y_{2}$ = 36.5

∵ $m=\frac{y_{2}-y_{1}}{x_{2}-x_{1}}$

∴ $m=\frac{-5-2}{36.5-1.5}=\frac{-7}{35}=\frac{-1}{5}$

∴ m = -0.2

∵ y = m x + b

∵ m = -0.2

∴ y = -0.2 x + b

- To find b substitute x and y in the equation by the coordinates of

one of the two given points

∵ x = 2 and y = 1.5

∴ 1.5 = -0.2(2) + b

∴ 1.5 = - 0.4 + b

- Add 0.4 to both sides

∴ 1.9 = b

∴ y = -0.2 x + 1.9

The equation of the line is y = -0.2 x + 1.9

∵ m = 4

∵ y = m x + b

∴ y = 4 x + b

∵ Point (3 , 15) lies on the line

- To find b substitute x and y in the equation by the coordinates

of the given point

∵ x = 3 and y = 15

∴ 15 = 4(3) + b

∴ 15 = 12 + b

- Subtract 12 from both sides

∴ 3 = b

∴ y = 4 x + 3

The equation of the line is y = 4 x + 3

∵ The line has the same slope of line y = 1

- The line whose equation y = 1 is a horizontal line

∵ The slope of the line y = 1 is zero because it is a horizontal line

∴ m = zero

∵ y = m x + b

∴ The equation of the line is y = (0)x + b

∴ y = b

∵ The line passes through point (3 , -8)

- In the horizontal line the y-coordinates of all point lie on the line

are equal

∴ The line intersect the y-axis at point (0 , -8)

∴ b = -8

∴ y = -8

The equation of the line is y = -8

∵ m = 2

∵ y-intercept is at point (0 , 4)

∴ b = 4

∵ y = m x + b

∴ y = 2 x + 4

The equation of the line is y = 2 x + 4

Learn more:

You can learn more about the linear equations in brainly.com/question/4326955

#LearnwithBrainly

6 0

3 years ago

Why does putting a lid over red cabbage help it keeps it color

Dahasolnce [82]

Answer:

It is blocking out some bacteria that feast on the cabbage.making it lose it's color.

Step-by-step explanation:

7 0

3 years ago

Two tangents drawn to a circle from a point outside it, are equal in length.prove it.​

Two tangents drawn to a circle from a point outside it, are equal in length.prove it.