Answer:
b. 80
Step-by-step explanation:
Mabel spends 4 hours editing a 3 minute video. she edits at a constant rate. how long does mabel spend to edit a 9 minute video?
she spends 4 hours on a 3 minute video
so there are 60 minutes in an hour
4 hours with 60 minutes- 4x60=240
so she spent 240 minutes on a 3 minute video
3 divided by 240
3/240= 0.0125
so her constant rate is 0.0125 minutes an hour
so divide 9 minutes by her constant rate
9/0.0125 = 720
so she spends 720 minutes on a 9 minute video.
divide 720 by 60 since there are 60 minutes in an hour
720/60 = 12
so she spends 12 hours on a 9minute video
Join the centre O to the chord (let it be MN) & let OH be the perpendicular to the chord
OH bisects MN into 2 equal parts (each one is x/2)
OMH is a right triangle with one side =8, the second leg =x/2 & the hypotenuse = 12 (Radius)
Apply Pythagoras:
12² = 8² +(x/2)² ==>144=64 + x²/4 ==> x²=4(144-64) =320
x²=320==> x=√320 =17.88 ≈17.9
-4x is the coefficient, 7 is the constant and x is the variable
Formula= Base times height divided by 2
6 x 7= 42
42/ 2
answer= 21
