Question

Which area formula or formulas show(s) a joint variation?

I. V = s^3


II. A = b x h


III. C = πd (this is the pie symbol next to the d)


a) I, II, and III



b) III only



c) II and III



d) II only

Answer 1

Option d

ii only.

Explanation:

1) V=s^3 got only one variable s. Hence when s is changed V is changed and vice versa. Not joint variation.

2) A=bxh

Here when area changes either b can change or h can change or both. For example if area 8 (4x2) is changed to 16, we can have either length unchanged (4x4) or width unchanged (8x2) or both changed as (4x4) Thus there is a joint variation for b and h here.

III.c=pi d

Here d is independent variable and c dependent variable. When d changes c changes directly and there is no joint variation.

So answer is d.