una dintre fetele laterale ale unei piramide patrulatere regulate este triunghi echilateral cu latura de 7cm. Calculati aria bazei piramidei consideratei

21.27 cm^2

Step-by-step explanation:

Pentru a calcula aria bazei, putem folosi formula lui Heron Matematic aceasta este;

A = √s (s-a) (s-b) (s-c)

Unde s = (a + b + c) / 2

a, b, c se referă la laturile triunghiului

A = (7 + 7 + 7) / 2 = 21/2 = 10,5

A = √10,5 (10,5-7) (10,5-7) (10,5-7)

A = √10,5 (3,5) (3,5) (3,5)

A = √450.1875

A = 21.2176 cm ^ 2, care este de aproximativ

21.22 cm ^ 2

answer: first option i.e. 'a' is correct.

step-by-step explanation:

since we have given that

number of minutes to wrap a small gift box = 4 minutes

we need to find the number of gifts to be wrapped in 5 minutes

since there is a direct variation, as the number of minutes will increase with   number of gifts to be wrapped.

so, let the number of gifts to be wrapped in 5 minutes be x.

so, it becomes,

hence, first option 'a'   is correct.