Answer:
141 5/7
Step-by-step explanation:
8c + 10b ÷ 7a
Let c = 7, b = 12, and a = 5
8*7 + 10*12 ÷ 7*5
Multiply and divide from left to right
56+120 ÷7*5
56+ 600/7
Get a common denominator
392/7 + 600/7
992/7
Change from an improper fraction to a mixed number
141 5/7
3. Look at the picture.
We have the right angle triangle. We know the sum of measures of angles in triangle is equal 180°. Therefore:


4.
Look at the picture.
Use Pythagorean theorem:



5.
TRUE: 1; 2; 4
6.
We find a slope of the line OP:

We have:

Now, we must find the slope of the line perpendicular to the line OP.
We know:

therefore

So. We have the answer! :)
Diameter is 18
radius is half of diameter so 9
area is radius*pi ^2 which is 88.83
circumference is diameter * pi so 18*pi = 56.55
The hardest part is finding the length of the curve at the top. To find arc length, multiply the circumference by the arc angle divided by full angle (360°) in a circle. Or:

x, the arc angle in a semicircle, is 180°.
r, the radius is 7/2 = 3.5.
Now just plug the numbers in and solve for arc length, s.
s = 2π(3.5)(1/2) ≈ 11.00
Now just add up all the sides. 11cm + 10cm + 10cm + 7cm = 38 cm.