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.

Answer:The length of BC = 28 unitsStep-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