Answer:
35.9 grams
Step-by-step explanation:
We use the formula:

Where
q is heat released
m is mass
C_p is the constant 2.44
ΔT is change in temperature
We put the info in the formula and solve for m (mass):

The mass of ethanol is 35.9 grams
Answer:
a) The formula for the area of a circle
Step-by-step explanation:
The formula for the area of a circle is
A = πr²
π is an irrational number and, no matter what value you use for r, the area will be an irrational number,
b) is wrong. A = ½(a + b)h.
c) is wrong. A = ½bh.
d) is wrong. A = bh.
All measurements are rational numbers, so the areas will be rational numbers.
Here we are finding x, given the angle and adjacent side. To find x we will use the function cos as cos = a/h.
So let's do cos(35°) = 15cm / x
cos(35°) = 0.8 (1 dp)
x = 15 cm / cos(35°)
x = 18.3 cm (1 dp)
X+y=57
y=x+15
x+x+15=57
2x=42
x=21
y=21+15
y=36