Diagram NOT accurately drown
28
A, B and Care points on a circle, centre 0
Angle ABC = 389
Work out the size of angle OAC
Give a reason for each stage of your working

m(∠OAC) = 52°

Step-by-step explanation:

A, B and C are the pints on a circle with center O.

m(∠ABC) = 38°

By the central angle theorem,

"Central angle subtended by two points on a circle measure the twice of the inscribed angle subtended by these points."

m(∠AOC) = 2m(∠ABC)

m(∠AOC) = 2 × 38° = 76°

Now in ΔAOC,

AO and OC are the radii, so the angles opposite to radii will measure the same.

∠OAC ≅ ∠OCA

Since, sum of all the interior angles of a triangle is 180°.

m(∠OAC) + m(∠OCA) + m(∠AOC) = 180°

m(∠OAC) + m(∠OAC) + 76° = 180°

2m(∠OAC) = 180° - 76°

2m(∠OAC) = 104°

m(∠OAC) = 52°

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for

b. y = 4x - 2

step-by-step explanation:

to find a parallel equation to an equation, make sure both equations have the same slope but different y-intercepts.

y = 4x + 1

4 = slope

1 = y-intercept

y = 4x - 2

4 = slope

-2 = y-intercept

they both have the same slope but different y-intercepts, so, b. is the correct answer.

and to check your work, you can graph both equations. : )