Answer:
see explanation
Step-by-step explanation:
Using the double angle identity for sine
sin2x = 2sinxcosx
Consider left side
cos20°cos40°cos80°
= 
(2sin20°cos20°)cos40°cos80°
= 
(2sin40°cos40°)cos80°
= (sin80°cos80° )
= 
(2sin80°cos80° )
= . sin160°
= . sin(180 - 20)°
= . sin20°
= 
= right side , thus proven
The last expression: (16-8)x2+4=8x6=48
Answer:
62.8 in2
Step-by-step explanation:
With round pizza we need to
find the area of each pizza in
square inches, then determine
the difference.
The area of a circle is given by:
A = πr2
12 inch diameter, radius = 6
a = π(62) = 36π in2
8 inch diameter, radius = 4
a = π(42) = 16π in2
Difference: 36π - 16π = 20π in2
using 3.14 for pi, the difference is
20(3.14) = 62.8 in2
2:10 and 4:20
therfor
1:5
times 5
5:25
answer is 25 minutes
