6/2 is the answer rise over run method
Answer:
Step-by-step explanation:
For a first order decay, fraction remaining = 0.5n where n = number of half lives elapsed.
fraction remaining = 55% = 0.55
0.55 = 0.5n
log 0.55 = n log 0.5
-0.2596 = -0.301 n
n = 0.8625 = # of half lives elapsed
0.8625 half lives x 2.5 billion years/half live = 2.16 billion years have elapsed = age of the rock
b) 0.15 = 0.5n
log 0.15 = n log 0.5
-0.824 = -0.301 n
n = 2.74 half lives
2.5 billion years/half life x 2.74 half lives = 6.85 billion years = age of rock
Answer:
Step-by-step explanation:
x + x + 65 °+ 25° = 180° ( being sum of angles of triangle )
2x + 90° = 180°
2x = 90°
x = 45
now
<A = 45°
< B = x + 65° = 45 °+ 65 °= 110°
< C = 25°
Hope it helps :)
