Answer:
Step-by-step explanation:

Keep the first fraction, change division to multiplication and find the reciprocal(multiplicative inverse) of the second fraction

1/4(r + 10) = r - 4 <== ur equation
1.78179743628 for "simplify root of 2 multiplied by the cube root of 2"
4/10 means 4 tenths (4 times 1/10)
4/10
0.4
2/5
40/100
40%
Area of big rectangle =8x7=56cm²
area of small rectangle =5x4=20cm²
hence area of shaded region=56-20=36cm²