Question

Please answer correctly !!!!!!!!!!!!!! Will mark Brianliest !!!!!!!!!!!!!!!!!!

Answer 1

Answer:

$\boxed {\boxed {\sf 1. \ 20 }}$

Step-by-step explanation:

An equilateral triangle has 3 equal sides and angles. Remember that equilateral sounds like equal.

The interior angles of a triangle must equal 180 degrees.

• All 3 angles are the same.
• 180/3= 60
• All 3 angles in an equilateral triangle equal 60 degrees.

The question tells us the angle is equal to (4x-20).

• ∠= 60°
• ∠= (4x-20)°

So, by substitution, we can set 60 and (4x-20) equal to each other.

$60=4x-20$

Now, solve for x by isolating the variable on one side of the equation.

20 is being subtracted from 4x and the inverse operation of subtraction is addition. Add 20 to both sides of the equation.

$20+60=4x-20+20 \\ 20+60=4x\\80=4x$

x is being multiplied by 4. The inverse operation of multiplication is division. Divide both sides of the equation by 4.

$\frac{80}{4}=\frac{4x}{4}$

$\frac{80}{4}=x \\\ 20=x$

x is equal to 20 and choice 1 is correct.