The diagram shows a right-angled triangle and a parallelogram.

16 cm height of triangle
30 cm base of parallelogram
9cm base of triangle

the area of the parallelogram is 5 times the area of the triangle.
the perpendicular height of the parallelogram is hcm.
(b) find the value of h.

Step-by-step explanation:

At= area of the triangle

Ap= area of the parallelogram

At=b*h/2=9*16/2=72

Ap=5*At=5*72=360

Ap=b*h=12⇒30*h=360⇒h=12

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this