Just need help on this one problem about a triangle

Given:

ΔABC is an equilateral triangle.

AB = 7.5x, BC = 6x + 3 and CA = 10x - 5

To find:

The value of x.

Solution:

In equilateral triangle, all sides are equal.

AB = BC = CA

Take any two sides only:

AB = BC

Subtract 6x from both sides.

Divide by 1.5 on both sides.

The value of x is 2.

answer:   28.56 feet (approx)

step-by-step explanation:

since, triangle abc has measure of angle c equal to 55 degrees, measure of angle abc equal to 90 degrees, and length of bc equal to 20 feet.

we have to find out the measurement of segment ab.

therefore, tan 55° =

but bc = 20 feet.

⇒ tan 55 ° =  

⇒ ab = 20 × tan 55 °

⇒ ab = 20 × 1.42814800674

⇒ ab = 28.5629601348   ≈ 28.56 feet