Let h = height of triangle
h^2 + 12^2 = 15^2
h^2 + 144 = 225
h^2 = 225 - 144
h^2 = 81
sqrt{h^2} = sqrt{81}
h = 9 cm
For part B, we need to find surface area because it represents the perimeter of this 3-D figure. The formula needed is SA = B + LA.
1. First find the lateral area.
LA = perimeter of triangle • height
LA = ph
p = 15 + 15 + 24
p = 30 + 24
p = 54 cm
LA = (54)(9)
LA = 486 cm^2
2. We now find the base of each triangle. This is found by finding the area of each triangle and multiplying by 2.
A = (1/2)bh
A = (1/2)(24)(9)
A = 108 cm^2
A = 2•108 cm^2
A = 216 cm^2 = our B in the surface area formula.
SA = B + LA
SA = 216 cm^2 + 486 cm^2
SA = 702 cm^2
The amount of cardboard needed is 702 cm^2.
Given:
and 
are complementary angles.
To find:
The measure of .
Solution:
According to the definition of the complimentary angles, the sum of two complementary angles is always 90 degree.
It is given that, and are complementary angles. So,
Therefore, the measure of is 58°.
Since it forms a "right triangle" we can apply trigonometry.
sin x = oppo/hyp
sin x = 13/20
x = sin^-1(13/20)
x = sin^-1(0.65)
x = 40.5
rounded to nearest degree
x = 41 degrees
Hope this helps! :)
