Question

The triangles are similar.

What is the value of x?

Enter your answer down below.
x =

(CLICK ON THE SCREENSHOT DOWN BELOW FOR MORE INFORMATION ABOUT THIS QUESTION.)

Answer 1

36/12=3 Which give you the enlargement of the smaller triangle to the bigger one.

You work out the missing side by putting it into an equation:

3(x-10)=39

Then solve it.

First expand the brackets:

3x-30=39

The rearrange to get x on its own and that will be your answer:

3x=39+30
3x=69
x=69/3
x=23

Answer 2

x=23

Explanation:

The triangles have to be in the same ratio. Put big triangle side over little triangle side.

15 39

----------- = ----------------

5 x-10

Using cross products

15 * (x-10) = 5 * 39

Divide by 15 on each side

15/15 (x-10) = 5*39/15

x-10 = 13

Add 10 to each side

x-10+10 = 13+10

x=23