There are 10 desks, 12 chairs and 4 cabinets. What's the ratio of chairs to all
items?

Step-by-step explanation:

By simply adding all of the items, you end up with 10 + 12 + 4, or 26 items.  Then, simply set the number of chairs to the number of total items, or 12 : 26.  This ratio can also be expressed as the fraction 12/26, and can be simplified into 6/13, or 6 : 13, by dividing both the numerator and denominator by 2.

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option a, c,d are correct.

step-by-step explanation:

from the given figure, it is given that z is equidistant from the sides of the triangle rst, then from triangle tzb and triangle szb, we have

tz=sz(given)

bz=zb(common)

therefore, by rhs rule,δtzb ≅δszb

by cpctc, sz≅tz

also, from δctz and δasz,

tz=sz(given)

∠tcz=∠saz(90°)

by rhs rule, δctz ≅ δasz, therefore by cpctc, ∠ctz≅∠asz

also,from δasz and δzsb,

zs=sz(common)

∠zbs=∠saz=90°

by rhs rule, δasz ≅δzsb, therefore, by cpctc, ∠asz≅∠zsb

hence, option a, c,d are correct.