Use pythagorean theorem

to find the opposite side, which is 7.3
so then you can just use inverse sinA=7.3/10 which equals 46.9 degrees
repeated mesurement can reduce the error
it is true
if you take any mesurement repeatedly and the average is taken, the error will be less
Answer:
B. 6HgO → 6Hg + 3O
Explanation:
A decomposition reaction is a reaction in which a single reactant is broken down into 2 or more products.
To solve this problem, we will get f and then we will use it to calculate the power.
So, for this farsighted person,
do = 25 cm and di = -80
Therefore:
1/f = (1/25) + (1/-80) = 0.00275 = 0.275 m
Power = 1/f = 1/0.275 = +3.6363 Diopeters.
This means that the lens is converging.