Answer:

Step-by-step explanation:
we are given r and the formula
we want to find the surface area of the shpare with the given r
to do so
we need our algebra skills
substitute the value of r:

recall law of exponent

to simplify:

simplify multiplication:

distribute:

hence our answer is F
C, because when you add 45 on both sides, and then after that when you have to subtract 15 in both sides, you get 0 = 120.
Answer:
8.75cm²
Step-by-step explanation:
First we need to find the angle subtended by the arc
L = theta/360 * 2pir
3.5 = theta/360 * 2*3.14(5)
3.5 = theta/360 * 31.4
theta/360 = 3.5/31.4
theta/360 = 0.11146
theta = 0.11146 * 360
theta = 40.13 degrees
Area of the sector = theta/360 * pir^2
Area of the sector = 40.13/360 * 3.14*25
Area of the sector = 40.13/360 * 78.5
Area of the sector = 8.75cm
Hence the area of the sector is 8.75cm²
Answer:

Step-by-step explanation:
First we calculate the number of possible ways to select 2 cards an ace and a card of 10 points.
There are 4 ace in the deck
There are 16 cards of 10 points in the deck
To make this calculation we use the formula of combinations

Where n is the total number of letters and r are chosen from them
The number of ways to choose 1 As is:

The number of ways to choose a 10-point letter is:

Therefore, the number of ways to choose an Ace and a 10-point card is:

Now the number of ways to choose any 2 cards from a deck of 52 cards is:


Therefore, the probability of obtaining an "blackjack" is:




