Determine first the difference between the incorrectly measured board and the correct one. The subtraction would result to 1.2 ft. The percent error is calculated by dividing this value by the correct value and then multiply by 100%. (1.2 ft / 12 ft) x 100% = 100%. Thus, the percent error is 10%.
Your answer is D because 10*2 is 20 and 6*2 is 12 so 12 out of the next 20 customers will purchase a sandwich.
To find the hypotenuse in a 45-45-90 triangle multiply the legs by

So...
The leg is 12 the hypotenuse is 12
Answer:
Option C is correct...hope this helps:)