Answer:

Step-by-step explanation:
Base of the isosceles triangle = 4
Perpendicular of the triangle = 3
In an isosceles triangle , a perpendicular bisects a base equally. So, here the isosceles triangle consist of 2 right angled triangles.
In that right angled triangles,
Base = 4/2 = 2 (∵ A perpendicular divides a base into 2 equal parts. )
Perpendicular = 3
Hypotenuse = x
So , according to Pythagorean Theorem ,

Using all the values above into the formula gives :-

Let's work on the left side first. And remember that
the<u> tangent</u> is the same as <u>sin/cos</u>.
sin(a) cos(a) tan(a)
Substitute for the tangent:
[ sin(a) cos(a) ] [ sin(a)/cos(a) ]
Cancel the cos(a) from the top and bottom, and you're left with
[ sin(a) ] . . . . . [ sin(a) ] which is [ <u>sin²(a)</u> ] That's the <u>left side</u>.
Now, work on the right side:
[ 1 - cos(a) ] [ 1 + cos(a) ]
Multiply that all out, using FOIL:
[ 1 + cos(a) - cos(a) - cos²(a) ]
= [ <u>1 - cos²(a)</u> ] That's the <u>right side</u>.
Do you remember that for any angle, sin²(b) + cos²(b) = 1 ?
Subtract cos²(b) from each side, and you have sin²(b) = 1 - cos²(b) for any angle.
So, on the <u>right side</u>, you could write [ <u>sin²(a)</u> ] .
Now look back about 9 lines, and compare that to the result we got for the <u>left side</u> .
They look quite similar. In fact, they're identical. And so the identity is proven.
Whew !
Since the question is asking how fast he is driving, we need to find his speed in miles per hour. To do this, you need to divide the amount of miles he drove by the amount of hours it took. When you do 412.5/7.5, you get the answer of 55 miles per hour.
Decimals are a number and a dot and more numbers
Answer:
x=146 degrees
Step-by-step explanation:
A supplementary angle is the conrisponding angle that adds to the other angle so it is 180. So 180-34= 146