Answer:
Look at the unfolded cylinder down: it's consisted of a rectangle and 2 circles. so to find the surface area of the cylinder we should find the areas of the rectangle and the 2 circles.
1) A of 2 circles = 2(π
) = 2π
2) A of rectangle = base x height (or length x width) = bh
but the if we fold the rectangle? what will happen?
the base will go around the circle, this means that the base is equal to the circle circumference, which is 2πr.
Therefore, A of rectangle = 2πrh
3) Surface area of cylinder = 2π + 2πrh
simplify more and take the common factor 2πr:
= 2πr (r+h)
Answer is
2. 15
3.- 18
4. 92
Make the fractions into improper fractions
4 5/7= 33/7 - Multiply the denominator with the whole number. 4*7=28, add 28 with the numerator. 28+5=33 .
6 3/7=45/7 - Multiply the denominator with the whole number. 6*7=42 , add 42 with the numerator. 42+3=45
33/7*45/7
Multiply the numerators together. Multiply the denominators together.
33*45=1485 ( numerators) , 7*7=49 ( denominators)
=1485/49 or in mixed number: 30 15/49
Answer: 1485/49 , 30 15/49
Step-by-step explanation: |x − y| = 1, ok lets play as Alice, my number is y, and the bob number is x.
the condition says that x-y = 1 or x-y = -1.
so, if you know x, then y = 1 +y or y = y - 1. so you have two possibilities.
let's see two cases : first, let's suppose there are no code in the conversation. Then the only way of being shure of your number, is if one of them have the lowest positive number, so the other should have the next one. So if Bob have the number one, Alice knows for shure that she has the 2. Bob knows that she has a 2, but that means he could have a 1 or a 3, but when he sees that Alice is shure about her number, he knows that his number is the 1.
the second case is where the conversation may be a sort of code, saying a phrase x times and changing when x = the number of the other person, in this case, bob will have the 201 and alice the 202.
Answer:
X=20
Y=70
Step-by-step explanation:
All angles within a triangle add up to 180
180 - 40 = 140
140 is the top angle of the big triangle
140 + x + x = 180
x = 20
Now use x to find y by subtracting from the right angle (90 degrees)
90 - 20 = 70
70 + 40 + y = 180
Y = 70
