Answer:
Step-by-step explanation:
Let base be b, height be h
h = 7+b or we can say that b = h -7
A = 15 cm²
General formula for area of a triangle
A = b · h
Substitute what we know to find the height h
15 = (h-7) · h
15 = h² -7h
0 = h²-7h -15
h = (7 ±√49 + 4·1·15)/2
h = (7 ±√109)/2
h ≈ -1.72 reject this solution because height cannot be negative
h ≈ 8.72 cm
