Answer:
∠B ≈ 56.25°
Step-by-step explanation:
Since the triangle is right use the cosine ratio to solve for B
cosB =
=
=
, thus
B =
(
) ≈ 56.25°
Answer:

Step-by-step explanation:

After removing one black marble:

Answer:
x = -8 +
62, -8 - √
62
Step-by-step explanation:
This is the exact form
In this question, we have to find the complement and supplement of the given angles .
Complementary angles are those angles whose sum is 90 degree and supplementary angles are those angles whose sum is 180 degree.
So to find the complement and supplement angles, we need to subtract the given angles from pi/2 and pi respectively .
a.

b.

The picture in the attached figure
we know that
surface area=2*area of the base+perimeter*height
area of the base=area of the triangle
area of the base=3*4/2----> 6 cm²
perimeter of the base=perimeter of triangle
perimeter=3+4+5----> 12 cm
height=x cm
surface area=2*6+12*x
surface area=204 cm²
12+12*x=204
12*x=204-12
12*x=192
x=192/12
x=16 cm
the answer is16 cm