They could look at the length of the book and the size of the font to estimate the length of a book.
Answer:

Step-by-step explanation:
Given
sinΘ =
= 
Then the hypotenuse = 5 and one leg of the right triangle is 3
Using Pythagoras' identity to find the second leg (x)
x² + 3² = 5²
x² + 9 = 25 ( subtract 9 from both sides )
x² = 16 ⇒ x = 4
cosΘ =
= 
Answer:
a/2 + b unidades
Step-by-step explanation:
Mi primera lengua es ingles (tienes paciencia por favor). Se da que la parte inferior es a/2 unidades. La parte anaranjada tiene un lado que es b/2, entonces todos los lados son b/2 tambien. Entonces el lado del derecho es b/2. La izquierda es b/2 tambien ( se da eso). Entonces el perimetro del triangulo amarillo es a/2 + b/2 + b/2 = a/2 + b unidades.
Answer:
13
Step-by-step explanation:
using BODMAS
13-11=2
SO 2*2=4
4/4=1
1*72=72
THEREFORE it is 85-72 =13
The sum of interior angles = (n-2) x 180 where n is the number of sides