The constant of proportionality is 2.5
Answer:

Step-by-step explanation:
First we solve for the biggest triangle: using the Pythagorean theorem, (a^2 + b^2 = c^2) we put in the sides,
9^2 + b^2 = 10^2.
solve, 81 + b^2 = 100
then we subtract 81 from both sides. b^2 = 19, and the answer is
.
Now we know what the third side is, which is the hypotenuse for the smaller triangle, so we use the Pythagorean theorem again.
4^2 + x^2 = 19.
Solve
16 + x^2 = 19
Subtract 16 from both sides
x^2 = 19
and finally, we take the square root of both sides
x = 
Answer:
Step-by-step explanation:
First we need to set this ratio up in the coordinate plane. Because this is tangent, the 3 goes opposite the reference angle and the 4 goes along the x-axis, adjacent to the reference angle. We see that we are missing the third side of the triangle when we do this, namely the hypotenuse. We use Pythagorean's Theorem to find that this side is 5. Now we have to deal with the identities for each sin(2A) and cos(2A).
sin(2A) = 2sin(A)cos(A)
We know from the triangle we drew in the coordinate plane that
and
so we fill in the formula accordingly and then simplify:

cos(2A) has 3 identities; I just picked the one I thought would be easiest to use and went with that one. Regardless of which one you pick you will get the same answer as long as you do the math correctly.
and filling in the formula:

I'm not sure why you have 7/2 there...
Answer:
d = - 22
Step-by-step explanation:
- 18 = d + 4 ( subtract 4 from both sides )
- 22 = d