In desperate need of help

see explanation

Step-by-step explanation:

∠ BOA = 360° - 250° = 110° ( sum of angles round a point )

∠ BDA is half the central angle, that is

∠ BDA = 0.5 × 110° = 55°

The angle between a tangent and the radius at the point of contact is 90°, thus

∠ OBC = ∠ OAC = 90°

The sum of the interior angles of quadrilateral OACB = 360°, thus

∠ BCA = 360° - (90 + 90 + 110)° = 360° - 290° = 70°

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.

the first one is x^2+2x+2

the second one is x^2+4

the last one is x^2-4x+8