What is the answer thx

The average human heart beats 1.15 \cdot 10^51.15⋅10 5 1, point, 15, dot, 10, start superscript, 5, end superscript times per day. there are 3.65 \cdot 10^23.65⋅10 2 3, point, 65, dot, 10, start superscript, 2, end superscript days in one year.how many times does the heart beat in one year? write your answer in scientific notation, and round to one decimal place.

What is the value of x when x + 7 = 21?

Given sin28.4=.4756, cos28.4=.8796, and tan28.4=.5407 find the cos of 61.6