Answer:
B. 10
Step-by-step explanation:
First, we need to recognize that the two triangles are similar (the triangle with a leg value of 21 and the triangle with a leg value of 4 and hypotenuse x)
Let's first label the leg of the second triangle as y.
Then, we can set up this equation

Cross multiplying gives us
84=y^2
So, y=sqrt(84) or 2 sqrt(21).
Now, using the pythagorean theorem, we get
4^2+2sqrt(21)^2=x^2
100=x^2
x=10
Answer:
Option C. 
Step-by-step explanation:
we know that
If two figures are similar, then the ratio of its corresponding sides is proportional
In this problem
Using proportion

Answer:
84211
Step-by-step explanation:
Got it right
Answer: -6 is your answer
Answer:
x > -4
Step-by-step explanation:
Inequalities like these are solved the same way equations are solved, except when multiplying both sides you flip the less than/greater than sign:
3x + 7 > -x -9
3x + 7 - 7 > -x -9 -7 Subtract 7 from both sides
3x > -x -16
3x + x > -x -16 + x add x to both sides
4x > -16
>
divide both sides by 4
x > -4
In this case the inequality sign did not have to be flipped since we never multiply both sides by a negative number.