Answer:
The answer to your question is 10.5 in
Step-by-step explanation:
Data
First triangle
height = x
base = 7 in
Second triangle
height = 12 in
base = 8 in
Process
1.- Use proportions to solve this problem, relates the sides of a triangle with the same sides of the other triangle.
2.- Multiply both sides by 7
3.- Simplify
x = 
4.- Result
x = 10.5 in
Answer:
20 units
Step-by-step explanation:
The perimeter of a rectangle is
P = 2(l+w)
P = 2( 3x+2 + 4x)
Adding like terms
P = 2( 7x+2)
We know the perimeter is 74 units
74 = 2 ( 7x+2)
Divide by 2
74/2 = 2/2 (7x+2)
37 = 7x+2
Subtract 2 from each side
37-2 = 7x+2-2
35 = 7x
Divide by 7
35/7 = 7x/7
5 =x
We want to find the length RS = PQ = 4x
RS = 4x = 4*5 = 20
You can do this 2 ways, one is knowing the special right triangles called triplets. An example of a triplet would be 3-4-5 where the largest value is the hypotenuse. In this example, the other 2 sides are 3 and 4 and the missing side is the hypotenuse, so using the knowledge of triplets, we can find that the hypotenuse is 5.
algebraically, we can use the Pythagorean theorem; a^2+b^2=c^2 where a and b are the opposite and adjacent and where c is the hypotenuse. We can then substitute in the values to get : 3^2 + 4^2 = c^2. When simplified, we get 9+16=c^2. Simplify further, and get 25=c^2. Now we Square root both sides to solve for C. Finally, we get C=5. Your missing side is 5.
