Hi there!

We know that the equation for the volume of a pyramid is:
V = 1/3(bh)
We know that:
V = 200 km³
b = 12 × 5 = 60 km²
We can plug these into the equation:
200 = 1/3(60)(h)
Simplify:
200 = 20h
Divide both sides by 20:
200/20 = 20h/20
h = 10 km
Answer:
There are 19 big marbles
Step-by-step explanation:
10a + 3b = 209
a = 3b
3b = 3b
10a + a = 209
11a = 209
a = 209/11
a = 19
Answer:
This was an observational study.
Step-by-step explanation:
Given is that parents of children completed a questionnaire on the child’s light exposure both at present and before the age of 2 years.
This was an observational study since there is no treatment or control group.
We know that treatment, control groups or treatment groups are not specific to randomized control experiments.
Remember that a percentage means "parts out of 100". 24% in decimal form is therefore 0.24, because it is 24 out of the possible 100, or 1.0. To find 24% of 75, you just multiply 0.24 times 75:
75 x 0.24 = 18
11 / 26 = 42% This answer is certainly correct for your percentage.