There are 360° in a circle and this circle is divided into 8 equal parts. 360/8 = 45 which means that each angle is 45°. The central angle subtended by minor arc BC is 2 portions of the circle, or 45 * 2 which is 90°. The answer is B.
Any number that we can write as a decimal number between 1.0 and 10.0, multiplied by a power of 10, is said to be in Scientific Notation. Some authors consider standard form and scientific form as the same, but others state that standard form is the common form of expressing numbers, i.e., a sequence of digits, separated by thousands by a comma, and separated from the decimal part by a dot.
We'll give here both answers.
We have to calculate:
Since the numbers don't have the same exponent, we must make them equal. Let's make the second number have an exponent of 5, by dividing by 10:
Now we add:
It's correctly expressed in scientific notation. Now to convert to 'standard form', multiply by :