A, B, C and D are points on the circumference of a circle, centre O. ED is a tangent to the circle.

E

Angle ODB = 25°

А

Work out angle BAD.

You must give a reason for each stage

of your working.

250

D

B

С

Total marks: 4

PLEASE HELPPP

Angle at BAD = 115°

Step-by-step explanation:

Angle at ODB = 25°

Step 1: Joining point B to the centre of the circle gives an equilateral triangle

Angle at OBD = 25° (base angles of an equilateral triangle are equal)

Angle at BOD = 180° - (25° + 25°) = 130° (sum of angles of a triangle = 180°)

Reflex angle at BOD = 360° - 130° = 230° (sum of angles at a point = 360°)

Step 2: Joining point B to A and point D to A gives another triangle

Angle at BAD = ½ × 230° = 115° (angle at centre is twice the angle at any point on the circumference)

Therefore, angle at BAD = 115°

center (1,3) with radius 6

step-by-step explanation:

we must complete the square to find the center and radius of the circle.

first make sure the x and y squared terms have 1 as their coefficients. we also make sure x and y terms together.

we now create space between the x and y terms with parenthesis.

we complete the square by taking the middle terms -2x and the -6y - divide each and square them.

we add the squares to both sides.

simplify.

and write the quadratics in factored form.

the center is (h,k) or (1,3). the radius is the square root of 36 which is 6.

step-by-step explanation:

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