What is the length of side bc of the triangle? enter your answer in the box. units triangle a b c with horizontal side b c. vertex a lies above side b c. angle b and angle c are marked congruent. the length of side a c is labeled as 2 x plus 7. the length of side a b is labeled as 4 x minus 7. the length of side b c is labeled as 4 x.

The length of BC = 28 units

Step-by-step explanation:

* In triangle ABC

∵ Angles B and C are congruent

∴ m∠B = m∠C

* In any triangle if two angles are equal in measure, then the triangle is isosceles means the two sides which opposite to the congruent angles are equal in length

∴ AB = AC

∵ AB = 4x - 7

∵ AC = 2x + 7

∴ 4x - 7 = 2x + 7 ⇒ collect like terms

∴ 4x - 2x = 7 + 7

∴ 2x = 14 ⇒ divide both sides by 2

∴ x = 14 ÷ 2 = 7

* Now we can find the length of BC

∵ The length of BC = 4x ⇒ substitute the value of x

∴ The length of BC = 4 × 7 = 28 units

the answer is b.6

step-by-step explanation: