D a theorem needs to be proven
Given:
5 bonds of face value of 1,000 that paid 5% annual interest rate.
5 bonds x 1,000 = 5,000
5,000 x 5% x 1 year = 250
The total annual interest income of James is 250. Each bond earns 50 per annum.
Answer:

Step-by-step explanation:
see the attached figure to better understand the problem
step 1
Find the length side KJ
In the right triangle JKM
Applying the Pythagoras Theorem

we have


substitute



simplify

step 2
Find the value of cosine of angle MJK in the right triangle JKM

substitute the values

simplify
-----> equation A
step 3
Find the value of cosine of angle MJK in the right triangle JKL

we have

----> remember equation A
substitute the values

Simplify
