Answer:
Step-by-step explanation:
Let the first number = x
Let the second number = x + 9
Let the third number = 4x
Together they make 123
x + x + 9 + 4x = 123 combine the left
6x + 9 = 123 Subtract 9 from both sides
6x = 123 - 9
6x = 114 Divide by 6
x = 114/6
x = 19
=================
First number = 19
Second number = 19 + 9 = 28
Third number = 4*19 = 76
Answer: 
Step-by-step explanation:
By definition, an Isosceles triangle has two equal sides and its opposite angles are congruent.
Observe the figure attached, where the isosceles triangle is divided into two equal right triangles.
So, in this case you need to use the following Trigonometric Identity:

In this case, you can identify that:

Substituting values, and solving for "x", you get:

Therefore, the length of BC rounded to nearest tenth, is:

For which side length? 10 or 8?