Yohanna is conditioning all summer to be fit for the next soccer season at his high school. he incorporated walking planks into his daily workout regime. each day, he will complete 4 more walking planks than the day before. if he starts with 5 walking planks on the first day, how many walking planks will he do on the twelfth day?

4 more than previous day
so
aritmetic sequence
first term is a1
common difference is d
an=a1+d(n-1)

first term is 5 planks
increases by 4 each day

an=5+4(n-1) is the equation for how many he will do on the nth day

12th day

a12=5+4(12-1)
a12=5+4(11)
a12=5+44
a12=49

49 walking planks

Answer: d. 39 cmin the diagram, the approximate length of the minor arc de is 39 centimetres.step-by-step explanation: the formula for the length of an arc in a circle is as displayed below.let the length of the minor arc de = xx = 2( pi )r × angle of sector / 360°from this, we will substitute the values given from the problem into the formula to obtain the length of the minor arc de.x = 2( pi )r × angle of sector / 360°r = radius = 25cmpi as an approximate value = 3.14angle of sector = 120°x = 2( 3.14 )( 25 ) × 120° / 360°x = 157 × 1 / 4x = 39.25x = 39 ( rounded to the nearest whole number as an approximate value )